Revert "Handle builder creation race condition with an exception"

This reverts commit d2a6153.

Author: Julien-Ben

scripts/release/build_images.py

@@ -46,7 +46,6 @@ def ecr_login_boto3(region: str, account_id: str):
 def ensure_buildx_builder(builder_name: str = DEFAULT_BUILDER_NAME) -> str:
     """
     Ensures a Docker Buildx builder exists for multi-platform builds.
-    This function is safe for concurrent execution across multiple processes.
 
     :param builder_name: Name for the buildx builder
     :return: The builder name that was created or reused
@@ -70,13 +69,6 @@ def ensure_buildx_builder(builder_name: str = DEFAULT_BUILDER_NAME) -> str:
         )
         logger.info(f"Created new buildx builder: {builder_name}")
     except DockerException as e:
-        # Check if this is a race condition (another process created the builder)
-        if hasattr(e, 'stderr') and 'existing instance for' in str(e.stderr):
-            logger.info(f"Builder '{builder_name}' was created by another process – using it.")
-            docker.buildx.use(builder_name)
-            return builder_name
-        
-        # Otherwise, it's a real error
         logger.error(f"Failed to create buildx builder: {e}")
         raise