Add missing vendor_available: true property

Due to b/424439549, Soong wasn't enforcing that vendor modules could only link against
other vendor modules.  Add vendor_available to any modules that are being used by
vendor modules in order to allow re-enabling the error in Soong.

Bug: 424439549
Flag: EXEMPT build only fix
Test: builds
Change-Id: I2216b83fc6fc271b5ad039dbb885bf79cf63b9a4