Bump latest released version of vertexai (#6241)

This was missed on the last mergeback that included vertexAI. Version
beta04 is already out

NO_RELEASE_CHANGE

Author: rlazo

firebase-vertexai/gradle.properties

@@ -12,5 +12,5 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-version=16.0.0-beta04
-latestReleasedVersion=16.0.0-beta03
+version=16.0.0-beta05
+latestReleasedVersion=16.0.0-beta04