go.mod: bump github.com/go-json-experiment/json (#15010)

The upstream module has seen significant work making
the v1 emulation layer a high fidelity re-implementation
of v1 "encoding/json".

This addresses several upstream breaking changes:
* MarshalJSONV2 renamed as MarshalJSONTo
* UnmarshalJSONV2 renamed as UnmarshalJSONFrom
* Options argument removed from MarshalJSONV2
* Options argument removed from UnmarshalJSONV2

Updates tailscale/corp#791

Signed-off-by: Joe Tsai <joetsai@digital-static.net>

util/syspolicy/internal/internal.go

@@ -56,10 +56,10 @@ func EqualJSONForTest(tb TB, j1, j2 jsontext.Value) (s1, s2 string, equal bool)
 		return "", "", true
 	}
 	// Otherwise, format the values for display and return false.
-	if err := j1.Indent("", "\t"); err != nil {
+	if err := j1.Indent(); err != nil {
 		tb.Fatal(err)
 	}
-	if err := j2.Indent("", "\t"); err != nil {
+	if err := j2.Indent(); err != nil {
 		tb.Fatal(err)
 	}
 	return j1.String(), j2.String(), false