feat: filter out *gapic.legacy.yaml when parsing java_gapic_opts (#2015)

Author: JoeWang1127

library_generation/test/resources/gapic_options/example_gapic.legacy.yaml

@@ -0,0 +1 @@
+# this file is only used in testing `get_gapic_opts` in utilities.sh

library_generation/test/resources/gapic_options/example_gapic_legacy.yaml

@@ -0,0 +1 @@
+# this file is only used in testing `get_gapic_opts` in utilities.sh

library_generation/utilities.sh

@@ -59,7 +59,7 @@ get_gapic_opts() {
     gapic_config="gapic-config=${gapic_config},"
   fi
   grpc_service_config=$(find "${proto_path}" -type f -name "*service_config.json")
-  api_service_config=$(find "${proto_path}" -maxdepth 1 -type f \( -name "*.yaml" ! -name "*gapic.yaml" \))
+  api_service_config=$(find "${proto_path}" -maxdepth 1 -type f \( -name "*.yaml" ! -name "*gapic*.yaml" \))
   if [ "${rest_numeric_enums}" == "true" ]; then
     rest_numeric_enums="rest-numeric-enums,"
   else