refactor(bigtable): remove duplicate fallback comments from shim call sites

Author: mutianf

java-bigtable/google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/internal/compat/ops/MutateRowShim.java

@@ -66,8 +66,6 @@ public boolean supports(RowMutation request) {
     } else {
       return false;
     }
-    // Currently this will only fallback in case RLS is misconfigured. If the AFE
-    // pool is unavailable, it'll be controlled by ClientConfiguration.
     return UnaryShim.shouldRouteToSession(pool);
   }
 

java-bigtable/google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/internal/compat/ops/ReadRowShim.java

@@ -78,8 +78,6 @@ public boolean supports(Query request) {
     } else {
       return false;
     }
-    // Currently this will only fallback in case RLS is misconfigured. If the AFE
-    // pool is unavailable, it'll be controlled by ClientConfiguration.
     return UnaryShim.shouldRouteToSession(pool);
   }