chore: use relative import in google_api_toolsets.py. Adds open source header for base_toolset.py

PiperOrigin-RevId: 762042799

src/google/adk/tools/base_toolset.py

@@ -1,3 +1,18 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
 from abc import ABC
 from abc import abstractmethod
 from typing import List

src/google/adk/tools/google_api_tool/google_api_toolsets.py

@@ -18,8 +18,7 @@ from typing import List
 from typing import Optional
 from typing import Union
 
-from google.adk.tools.base_toolset import ToolPredicate
-
+from ..base_toolset import ToolPredicate
 from .google_api_toolset import GoogleApiToolset
 
 logger = logging.getLogger("google_adk." + __name__)