chore: remove discovery artifact copy from synth.py (#1206)

Discovery artifacts will be updated by the GitHub Action, see #1187

synth.py

@@ -14,9 +14,7 @@
 
 import synthtool as s
 from synthtool import gcp
-from synthtool.sources import git
 
-DISCOVERY_ARTIFACT_MANAGER_REPO = "googleapis/discovery-artifact-manager"
 
 common = gcp.CommonTemplates()
 
@@ -32,19 +30,6 @@
 # Also move issue templates
 s.move(templated_files / '.github')
 
-# ----------------------------------------------------------------------------
-# Copy discoveries folder from discovery-artifact-manager repo
-# ----------------------------------------------------------------------------
-
-discovery_artifact_manager_url = git.make_repo_clone_url(DISCOVERY_ARTIFACT_MANAGER_REPO)
-discovery_artifacts = git.clone(discovery_artifact_manager_url) / "discoveries"
-
-excludes = [
-    "**/BUILD.bazel",
-]
-s.copy(discovery_artifacts,
-       "googleapiclient/discovery_cache/documents", excludes=excludes)
-
 # ----------------------------------------------------------------------------
 # Generate docs
 # ----------------------------------------------------------------------------