Install/run mods on first deployment install on extension startup

[twschiller]

Context

• As an enterprise mod admin for a compliance mod, I want deployments to run on existing tabs on initial deployment activation (as opposed to queuing for the next frame navigation)
• Historically, PixieBrix does not inject deployments into existing frames so as to not interfere with user's ongoing chat sessions, etc. Instead it queues them to load on the next navigation (including SPA navigation)

Definition of Done

• On the first deployment update after extension startup (track using session storage), install/run mods on existing tabs rather than just queuing those mods. (To clarify, this is not per deployment, but overall)

Related Code

• https://github.com/pixiebrix/pixiebrix-extension/blob/870a6c3f2bf48aeecf4598eea02c4d32c2907746/src/background/deploymentUpdater.ts#L325-L325

Related Issues

• https://github.com/pixiebrix/pixiebrix-extension/issues/8740