GAM 7.48.17 (automated bump)

[github-actions]

Automated bump of the vendored GAM, 7.48.14 → 7.48.17, via scripts/bump_gam.py.

• Asset build-attestation verified (signed by GAM-team/GAM's release workflow on main) before the pin was written.
• Pin, version strings, test mock, browse catalog and the counts in CLAUDE.md, README and ROADMAP updated mechanically.
• ✅ offline suite green

Before merge (human): click Approve and run workflows so CI and CodeQL run on this PR
(a PR opened by github.token doesn't start them), and merge only once the required checks are
green. Skim the changelog below, and run scripts/acceptance.py against a real tenant — CI
cannot (it is the only true output-shape check). If the suite is red, the contract test likely
caught a renamed/removed command we use; that needs a code change.

GamUpdate.txt since 7.48.14

7.48.17

`gam <UserTypeEntity> print|show chatsearchmessages` are no longer in Developer Preview.

7.48.16

Added option `comments default|included|omitted` to `gam <UserTypeEntity> get document`
to enable display of document comments.

7.48.15

Addded `showownorganizationonly` to `<CalendarSelectProperty>` that is by used by commands that list
a user's calendars to show only entries for calendars from the organization.

Updated `gam delete|print|show policies` to handle the following error:
`ERROR: 503: serviceNotAvailable - The service is currently unavailable.`