rebase: bump google.golang.org/grpc from 1.49.0 to 1.50.1

Bumps [google.golang.org/grpc](https://github.com/grpc/grpc-go) from 1.49.0 to 1.50.1.
- [Release notes](https://github.com/grpc/grpc-go/releases)
- [Commits](https://github.com/grpc/grpc-go/compare/v1.49.0...v1.50.1)

---
updated-dependencies:
- dependency-name: google.golang.org/grpc
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

vendor/google.golang.org/grpc/internal/envconfig/observability.go

@@ -0,0 +1,36 @@
+/*
+ *
+ * Copyright 2022 gRPC authors.
+ *
+ * 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.
+ *
+ */
+
+package envconfig
+
+import "os"
+
+const (
+	envObservabilityConfig     = "GRPC_GCP_OBSERVABILITY_CONFIG"
+	envObservabilityConfigFile = "GRPC_GCP_OBSERVABILITY_CONFIG_FILE"
+)
+
+var (
+	// ObservabilityConfig is the json configuration for the gcp/observability
+	// package specified directly in the envObservabilityConfig env var.
+	ObservabilityConfig = os.Getenv(envObservabilityConfig)
+	// ObservabilityConfigFile is the json configuration for the
+	// gcp/observability specified in a file with the location specified in
+	// envObservabilityConfigFile env var.
+	ObservabilityConfigFile = os.Getenv(envObservabilityConfigFile)
+)