[runtimes][NFC] Re-indent shared library blocks (#205523)

Re-indent the shared library target blocks that were wrapped in
if(<runtime>_SUPPORTS_SHARED_LIBRARY) in the previous commit. This is a
whitespace-only change split out from the functional change to keep that
diff minimal and reviewable.

Co-authored-by: Claude (Opus 4.8) <noreply@anthropic.com>
GitOrigin-RevId: 6a909d68627ff6027777186699ff8fd54ae6e668