Revert "[ChromeVox] Convert ISearchHandler to TypeScript"

This reverts commit 1c9d1208.

Reason for revert: Causing failures on linux-presubmit, see crbug.com/346390282.

Original change's description:
> [ChromeVox] Convert ISearchHandler to TypeScript
>
> AX-Relnotes: n/a.
> Bug: b/267329383
> Change-Id: I5ab7bdb3f75978d263596420f46e84d35e0927e2
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5600080


> Commit-Queue: Anastasia Helfinstein <anastasi@google.com>
> Reviewed-by: Kyungjun Lee <kyungjunlee@google.com>
> Cr-Commit-Position: refs/heads/main@{#1312932}

Bug: b/267329383
Change-Id: I1588df4d78284f1fa38bf3c3cb293985f2f82600
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5617171
Commit-Queue: Adithya Srinivasan <adithyas@chromium.org>
Auto-Submit: Adithya Srinivasan <adithyas@chromium.org>
Owners-Override: Adithya Srinivasan <adithyas@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1313021}