rebase: bump google.golang.org/grpc from 1.55.0 to 1.56.0

Bumps [google.golang.org/grpc](https://github.com/grpc/grpc-go) from 1.55.0 to 1.56.0.
- [Release notes](https://github.com/grpc/grpc-go/releases)
- [Commits](https://github.com/grpc/grpc-go/compare/v1.55.0...v1.56.0)

---
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/service_config.go

@@ -23,8 +23,6 @@ import (
 	"errors"
 	"fmt"
 	"reflect"
-	"strconv"
-	"strings"
 	"time"
 
 	"google.golang.org/grpc/codes"
@@ -106,8 +104,8 @@ type healthCheckConfig struct {
 
 type jsonRetryPolicy struct {
 	MaxAttempts          int
-	InitialBackoff       string
-	MaxBackoff           string
+	InitialBackoff       internalserviceconfig.Duration
+	MaxBackoff           internalserviceconfig.Duration
 	BackoffMultiplier    float64
 	RetryableStatusCodes []codes.Code
 }
@@ -129,50 +127,6 @@ type retryThrottlingPolicy struct {
 	TokenRatio float64
 }
 
-func parseDuration(s *string) (*time.Duration, error) {
-	if s == nil {
-		return nil, nil
-	}
-	if !strings.HasSuffix(*s, "s") {
-		return nil, fmt.Errorf("malformed duration %q", *s)
-	}
-	ss := strings.SplitN((*s)[:len(*s)-1], ".", 3)
-	if len(ss) > 2 {
-		return nil, fmt.Errorf("malformed duration %q", *s)
-	}
-	// hasDigits is set if either the whole or fractional part of the number is
-	// present, since both are optional but one is required.
-	hasDigits := false
-	var d time.Duration
-	if len(ss[0]) > 0 {
-		i, err := strconv.ParseInt(ss[0], 10, 32)
-		if err != nil {
-			return nil, fmt.Errorf("malformed duration %q: %v", *s, err)
-		}
-		d = time.Duration(i) * time.Second
-		hasDigits = true
-	}
-	if len(ss) == 2 && len(ss[1]) > 0 {
-		if len(ss[1]) > 9 {
-			return nil, fmt.Errorf("malformed duration %q", *s)
-		}
-		f, err := strconv.ParseInt(ss[1], 10, 64)
-		if err != nil {
-			return nil, fmt.Errorf("malformed duration %q: %v", *s, err)
-		}
-		for i := 9; i > len(ss[1]); i-- {
-			f *= 10
-		}
-		d += time.Duration(f)
-		hasDigits = true
-	}
-	if !hasDigits {
-		return nil, fmt.Errorf("malformed duration %q", *s)
-	}
-
-	return &d, nil
-}
-
 type jsonName struct {
 	Service string
 	Method  string
@@ -201,7 +155,7 @@ func (j jsonName) generatePath() (string, error) {
 type jsonMC struct {
 	Name                    *[]jsonName
 	WaitForReady            *bool
-	Timeout                 *string
+	Timeout                 *internalserviceconfig.Duration
 	MaxRequestMessageBytes  *int64
 	MaxResponseMessageBytes *int64
 	RetryPolicy             *jsonRetryPolicy
@@ -252,15 +206,10 @@ func parseServiceConfig(js string) *serviceconfig.ParseResult {
 		if m.Name == nil {
 			continue
 		}
-		d, err := parseDuration(m.Timeout)
-		if err != nil {
-			logger.Warningf("grpc: unmarshaling service config %s: %v", js, err)
-			return &serviceconfig.ParseResult{Err: err}
-		}
 
 		mc := MethodConfig{
 			WaitForReady: m.WaitForReady,
-			Timeout:      d,
+			Timeout:      (*time.Duration)(m.Timeout),
 		}
 		if mc.RetryPolicy, err = convertRetryPolicy(m.RetryPolicy); err != nil {
 			logger.Warningf("grpc: unmarshaling service config %s: %v", js, err)
@@ -312,18 +261,10 @@ func convertRetryPolicy(jrp *jsonRetryPolicy) (p *internalserviceconfig.RetryPol
 	if jrp == nil {
 		return nil, nil
 	}
-	ib, err := parseDuration(&jrp.InitialBackoff)
-	if err != nil {
-		return nil, err
-	}
-	mb, err := parseDuration(&jrp.MaxBackoff)
-	if err != nil {
-		return nil, err
-	}
 
 	if jrp.MaxAttempts <= 1 ||
-		*ib <= 0 ||
-		*mb <= 0 ||
+		jrp.InitialBackoff <= 0 ||
+		jrp.MaxBackoff <= 0 ||
 		jrp.BackoffMultiplier <= 0 ||
 		len(jrp.RetryableStatusCodes) == 0 {
 		logger.Warningf("grpc: ignoring retry policy %v due to illegal configuration", jrp)
@@ -332,8 +273,8 @@ func convertRetryPolicy(jrp *jsonRetryPolicy) (p *internalserviceconfig.RetryPol
 
 	rp := &internalserviceconfig.RetryPolicy{
 		MaxAttempts:          jrp.MaxAttempts,
-		InitialBackoff:       *ib,
-		MaxBackoff:           *mb,
+		InitialBackoff:       time.Duration(jrp.InitialBackoff),
+		MaxBackoff:           time.Duration(jrp.MaxBackoff),
 		BackoffMultiplier:    jrp.BackoffMultiplier,
 		RetryableStatusCodes: make(map[codes.Code]bool),
 	}