rebase: bump google.golang.org/grpc from 1.71.1 to 1.72.0

Bumps [google.golang.org/grpc](https://github.com/grpc/grpc-go) from 1.71.1 to 1.72.0.
- [Release notes](https://github.com/grpc/grpc-go/releases)
- [Commits](https://github.com/grpc/grpc-go/compare/v1.71.1...v1.72.0)

---
updated-dependencies:
- dependency-name: google.golang.org/grpc
  dependency-version: 1.72.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

vendor/google.golang.org/grpc/internal/metadata/metadata.go

@@ -97,13 +97,11 @@ func hasNotPrintable(msg string) bool {
 	return false
 }
 
-// ValidatePair validate a key-value pair with the following rules (the pseudo-header will be skipped) :
-//
-// - key must contain one or more characters.
-// - the characters in the key must be contained in [0-9 a-z _ - .].
-// - if the key ends with a "-bin" suffix, no validation of the corresponding value is performed.
-// - the characters in the every value must be printable (in [%x20-%x7E]).
-func ValidatePair(key string, vals ...string) error {
+// ValidateKey validates a key with the following rules (pseudo-headers are
+// skipped):
+// - the key must contain one or more characters.
+// - the characters in the key must be in [0-9 a-z _ - .].
+func ValidateKey(key string) error {
 	// key should not be empty
 	if key == "" {
 		return fmt.Errorf("there is an empty key in the header")
@@ -119,6 +117,20 @@ func ValidatePair(key string, vals ...string) error {
 			return fmt.Errorf("header key %q contains illegal characters not in [0-9a-z-_.]", key)
 		}
 	}
+	return nil
+}
+
+// ValidatePair validates a key-value pair with the following rules
+// (pseudo-header are skipped):
+//   - the key must contain one or more characters.
+//   - the characters in the key must be in [0-9 a-z _ - .].
+//   - if the key ends with a "-bin" suffix, no validation of the corresponding
+//     value is performed.
+//   - the characters in every value must be printable (in [%x20-%x7E]).
+func ValidatePair(key string, vals ...string) error {
+	if err := ValidateKey(key); err != nil {
+		return err
+	}
 	if strings.HasSuffix(key, "-bin") {
 		return nil
 	}