[FilesBulkPinning] Fix null and not-enough-space type errors

The lit fromAttribute converter can receive null when the attribute is
removed, this happens during a state transition or when the feature is
turned off and thus can lead to log spam.

Further the not-enough-space enum was being converted to uppercase and
checked against the existing values, as the check is against the keys it
was trying to match NOT-ENOUGH-SPACE against NOT_ENOUGH_SPACE which was
throwing up log spam. Align the 2.

Fixed: b:281949382
Test: browser_tests --gtest_filter=*XfCloudPanel*
Change-Id: I3d4a7a34e250a61f3e9207280e6aff18f3d4826a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4564993


Commit-Queue: François Degros <fdegros@chromium.org>
Reviewed-by: François Degros <fdegros@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1149446}