refactor(ui5-shellbar): introducing assistant slot

[plamenivanov91]

Тhe showCoPilot property and the co-pilot-click event of the ui5-shellbar have been removed. In their place we now have a public slot called assistant. We recommend using ui5-toggle-button with sap-icon://da and sap-icon://da-2 icons (see the examples below).

BREAKING CHANGE:

1. The showCoPilot property of the ui5-shellbar is removed.

If you have previously used the showCoPilot property:

<ui5-shellbar show-co-pilot></ui5-shellbar>

it will no longer work for the component.

2. The CoPilotAnimation feature of the ui5-shellbar is removed.

If you have previously used the CoPilotAnimation feature:

import CoPilotAnimation from "@ui5/webcomponents-fiori/dist/features/CoPilotAnimation.js"

it will no longer work for the component.

3. The copilotDomRef getter of the ui5-shellbar is removed.

If you have previously used the copilotDomRef public getter:

shellbar.copilotDomRef

it will no longer work for the component.

4. The co-pilot-click event of the ui5-shellbar is removed. If you have previously used the co-pilot-click public event:

shellbar.addEventListener("ui5-co-pilot-click", function(event) {
	...
});

it will no longer work for the component.

You can achieve similar functionality with the new slot:

HTML:

<ui5-shellbar>
  <ui5-toggle-button id="assistant" icon="sap-icon://da" slot="assistant"></ui5-toggle-button>
</ui5-shellbar>

JavaScript:

assistant.addEventListener("click", function (event) {
	const toggleButton = event.target;
	toggleButton.icon = toggleButton.pressed ? "sap-icon://da-2" : "sap-icon://da";
});

Related to #8461, #7887

[vladitasev]

Please add instructions in the BREAKING CHANGES section how users can achieve the old behavior or similar.

[vladitasev]

@IlianaB When I reviewed this change I noticed a test not failing although the used selector for the new test does not match anything on the page. Then I discovered these setTimeout and that tests may fail within them without causing an error because somehow the setTimeout interferes with the lifecycle of the test (probably is not awaited for).

[cla-assistant[bot]]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
2 out of 3 committers have signed the CLA.

:white_check_mark: plamenivanov91
:white_check_mark: PetyaMarkovaBogdanova
:x: Nayden Naydenov

---

Nayden Naydenov seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[cla-assistant[bot]]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

:white_check_mark: plamenivanov91
:x: PetyaMarkovaBogdanova
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[cla-assistant[bot]]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
2 out of 3 committers have signed the CLA.

:white_check_mark: plamenivanov91
:white_check_mark: PetyaMarkovaBogdanova
:x: Nayden Naydenov

---

Nayden Naydenov seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[cla-assistant[bot]]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
2 out of 3 committers have signed the CLA.

:white_check_mark: PetyaMarkovaBogdanova
:white_check_mark: plamenivanov91
:x: Nayden Naydenov

---

Nayden Naydenov seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[plamenivanov91]

Superseded by https://github.com/SAP/ui5-webcomponents/pull/8963