Wait for agent loop to finish in automation (#262370)

* add `workbench.action.chat.open::waitForComplete`

* s/waitForCompletion/blockOnResponse

* cleanup tests

* remove unused comment

* Apply suggestion from @connor4312

Co-authored-by: Connor Peet <[email protected]>

* fixup tests

* don't block test loop on invokeTool

* Revert "don't block test loop on invokeTool"

This reverts commit d8d16dbe79fda2538cdb5bfb743158c6348ecf4b.

* fix tool confirmation test

* attempt to account for the flip of isPendingConfirmation

* [DEBUG] debug CI flake

* register tool so it exists in all test envs

* finish configuring custom tool

* run test in seperate chat windows

* revert debug changes

* remove timeout dep

* fix assertion

* cleaup tests by examining output of command directly

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Co-authored-by: Connor Peet <[email protected]>