Revert "NPT Promos: Finchify shown promo counts"

This reverts commit bcc483421f8c443459ad38db8974a2623db01569.

Reason for revert: Multiple tests failures in interactive_ui_tests on linux64-rel-ready.

Bug: 440478789

Original change's description:
> NPT Promos: Finchify shown promo counts
>
> This ties the number of promos shown (eligible and completed) to
> Finch. Note that the two-promo arm of this experiment is done by
> choosing single-promo mode and setting the promo count to two.
>
> Change-Id: I6090579d5cef3f3119d8ac374e7f80580eae0c84
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6871055
> Reviewed-by: Dana Fried <dfried@chromium.org>
> Commit-Queue: Christopher Grant <cjgrant@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1504849}

No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Change-Id: I7c026a9e8811e3559bda3c9d64ba989005b3fb33
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6874202
Commit-Queue: Shunya Shishido <sisidovski@chromium.org>
Owners-Override: Shunya Shishido <sisidovski@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1504880}