rebase: bump google.golang.org/grpc from 1.72.2 to 1.73.0

Bumps [google.golang.org/grpc](https://github.com/grpc/grpc-go) from 1.72.2 to 1.73.0.
- [Release notes](https://github.com/grpc/grpc-go/releases)
- [Commits](https://github.com/grpc/grpc-go/compare/v1.72.2...v1.73.0)

---
updated-dependencies:
- dependency-name: google.golang.org/grpc
  dependency-version: 1.73.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

vendor/google.golang.org/grpc/credentials/credentials.go

@@ -120,6 +120,20 @@ type AuthInfo interface {
 	AuthType() string
 }
 
+// AuthorityValidator validates the authority used to override the `:authority`
+// header. This is an optional interface that implementations of AuthInfo can
+// implement if they support per-RPC authority overrides. It is invoked when the
+// application attempts to override the HTTP/2 `:authority` header using the
+// CallAuthority call option.
+type AuthorityValidator interface {
+	// ValidateAuthority checks the authority value used to override the
+	// `:authority` header. The authority parameter is the override value
+	// provided by the application via the CallAuthority option. This value
+	// typically corresponds to the server hostname or endpoint the RPC is
+	// targeting. It returns non-nil error if the validation fails.
+	ValidateAuthority(authority string) error
+}
+
 // ErrConnDispatched indicates that rawConn has been dispatched out of gRPC
 // and the caller should not close rawConn.
 var ErrConnDispatched = errors.New("credentials: rawConn is dispatched out of gRPC")
@@ -207,14 +221,32 @@ type RequestInfo struct {
 	AuthInfo AuthInfo
 }
 
+// requestInfoKey is a struct to be used as the key to store RequestInfo in a
+// context.
+type requestInfoKey struct{}
+
 // RequestInfoFromContext extracts the RequestInfo from the context if it exists.
 //
 // This API is experimental.
 func RequestInfoFromContext(ctx context.Context) (ri RequestInfo, ok bool) {
-	ri, ok = icredentials.RequestInfoFromContext(ctx).(RequestInfo)
+	ri, ok = ctx.Value(requestInfoKey{}).(RequestInfo)
 	return ri, ok
 }
 
+// NewContextWithRequestInfo creates a new context from ctx and attaches ri to it.
+//
+// This RequestInfo will be accessible via RequestInfoFromContext.
+//
+// Intended to be used from tests for PerRPCCredentials implementations (that
+// often need to check connection's SecurityLevel). Should not be used from
+// non-test code: the gRPC client already prepares a context with the correct
+// RequestInfo attached when calling PerRPCCredentials.GetRequestMetadata.
+//
+// This API is experimental.
+func NewContextWithRequestInfo(ctx context.Context, ri RequestInfo) context.Context {
+	return context.WithValue(ctx, requestInfoKey{}, ri)
+}
+
 // ClientHandshakeInfo holds data to be passed to ClientHandshake. This makes
 // it possible to pass arbitrary data to the handshaker from gRPC, resolver,
 // balancer etc. Individual credential implementations control the actual