Remove timer faking from functionWatcher tests

[lopert]

WHY are these changes introduced?

Part of https://github.com/Shopify/shopify-functions/issues/481

This test was reported as flakey, so this attempts to fix it by removing the unnecessary timer faking.

WHAT is this pull request doing?

Swaps out our timer faking with a more straightforward waitFor that just checks the last returned result from our hook function until it matches what we expect.

I used waitFor from cli-kit's testing/ui, and had to add it to the public export.
I figured this was fine, but if it's not I could also copy the code from it into our tests more directly.

I also looked at usePollAppLogsTest where we used a similar approach, but I chose to keep it as is over there since that test has a lot to do with timing, retries, and enqueued timers. It makes sense over there.

How to test your changes?

p vitest function/ui

Post-release steps

N/A

Measuring impact

How do we know this change was effective? Please choose one:

• n/a - this doesn't need measurement, e.g. a linting rule or a bug-fix
• Existing analytics will cater for this addition
• PR includes analytics changes to measure impact

Checklist

• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've considered possible documentation changes

[github-actions]

Differences in type declarations

We detected differences in the type declarations generated by Typescript for this branch compared to the baseline ('main' branch). Please, review them to ensure they are backward-compatible. Here are some important things to keep in mind:

• Some seemingly private modules might be re-exported through public modules.
• If the branch is behind main you might see odd diffs, rebase main into this branch.

New type declarations

We found no new type declarations in this PR

Existing type declarations

packages/cli-kit/dist/public/node/testing/ui.d.ts

@@ -1 +1 @@
-export { getLastFrameAfterUnmount, render, Stdin, waitForInputsToBeReady, waitForContent, sendInputAndWait, sendInputAndWaitForChange, sendInputAndWaitForContent, } from '../../../private/node/testing/ui.js';
\ No newline at end of file
+export { getLastFrameAfterUnmount, render, Stdin, waitFor, waitForInputsToBeReady, waitForContent, sendInputAndWait, sendInputAndWaitForChange, sendInputAndWaitForContent, } from '../../../private/node/testing/ui.js';
\ No newline at end of file

[github-actions]

We detected some changes at packages/*/src and there are no updates in the .changeset.
If the changes are user-facing, run "pnpm changeset add" to track your changes and include them in the next release CHANGELOG.

[github-actions]

Coverage report

St.❔	Category	Percentage	Covered / Total
🟡	Statements	75.32% (+0% 🔼)	8841/11738
🟡	Branches	70.58% (+0.01% 🔼)	4290/6078
🟡	Functions	75.2% (-0.01% 🔻)	2314/3077
🟡	Lines	75.85% (-0% 🔻)	8357/11018

Show files with reduced coverage 🔻

St.❔	File	Statements	Branches	Functions	Lines
🟢	... / identifiers.ts	96.23% (-3.77% 🔻)	89.19% (-1.29% 🔻)	100%	100%
🟢	... / ConcurrentOutput.tsx	98.36% (-1.64% 🔻)	88% (-4% 🔻)	100%	98.33% (-1.67% 🔻)

Test suite run success

1994 tests passing in 900 suites.

Report generated by 🧪jest coverage report action from fd3bf4a