chore: Combine go files generated from the grpc asset's protobuf definitions

[ctlong]

Are you submitting this PR against the develop branch?

Yes

What is this change about?

Refactors CATs to not require manually copying and pasting the go files generated from the grpc asset's protobuf definitions whenever we regenerate them.

Also regenerates the go files.

Please provide contextual information.

None

What version of cf-deployment have you run this cf-acceptance-test change against?

None yet

Please check all that apply for this PR:

• [x] refactor
• [ ] introduces a new test --- Are you sure everyone should be running this test?
• [ ] changes an existing test
• [ ] requires an update to a CATs integration-config

Did you update the README as appropriate for this change?

• [ ] YES
• [x] N/A

If you are introducing a new acceptance test, what is your rationale for including it CATs rather than your own acceptance test suite?

N/A

How many more (or fewer) seconds of runtime will this change introduce to CATs?

None

What is the level of urgency for publishing this change?

• [ ] Urgent - unblocks current or future work
• [x] Slightly Less than Urgent

Tag your pair, your PM, and/or team!

None