[clippy] Override manifest id for the M365 PWA on ChromeOS

In order to have certainty that the M365 PWA id stays consistent
if the Url is not changed entirely, the manifest id is overridden
to erase any potential small Url changes, especially changes of
the query parameters. This needs to be done in order to guarantee
all Clippy integrations to continue to work as expected if there
are smaller changes in the M365 navigation.
For more context, see go/clippy-m365-rebranding.

Bug: b:389599427
Change-Id: I78ddfb9a591ad7a1b97fa50c6d36f83cf4dbd249
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6268647
Reviewed-by: Alexander Bolodurin <alexbn@chromium.org>
Reviewed-by: Dibyajyoti Pal <dibyapal@chromium.org>
Commit-Queue: Leon Masopust <lmasopust@google.com>
Cr-Commit-Position: refs/heads/main@{#1421841}