[ty] Skip flaky symlink file-watching test (#28702)
`symlink_inside_project` intermittently fails in Linux CI because the
indexed project files unexpectedly include the symlinked `bar/baz.py`
path. Ignore the test temporarily and add a TODO to re-enable it once
symlink file-watching is reliable in CI.
## Test plan
No new tests are added. The existing test remains available to run
explicitly, and the other symlink file-watching tests remain enabled
where supported.
