Optimize marshalling for jsonb types (#19898)

We check for the presence of binary_parameters
in the DSN and add the 0x01 byte accordingly.

This helps us avoid casting to string
and efficiently use the database.

```release-note
NONE
```

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

model/utils.go

@@ -33,6 +33,7 @@ const (
 	UppercaseLetters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 	NUMBERS          = "0123456789"
 	SYMBOLS          = " !\"\\#$%&'()*+,-./:;<=>?@[]^_`|~"
+	BinaryParamKey   = "MM_BINARY_PARAMETERS"
 )
 
 type StringInterface map[string]interface{}
@@ -124,12 +125,19 @@ func (m *StringMap) Scan(value interface{}) error {
 
 // Value converts StringMap to database value
 func (m StringMap) Value() (driver.Value, error) {
-	j, err := json.Marshal(m)
+	ok := m[BinaryParamKey]
+	delete(m, BinaryParamKey)
+	buf, err := json.Marshal(m)
 	if err != nil {
 		return nil, err
 	}
-	// non utf8 characters are not supported https://mattermost.atlassian.net/browse/MM-41066
-	return string(j), err
+	if ok == "true" {
+		return append([]byte{0x01}, buf...), nil
+	} else if ok == "false" {
+		return buf, nil
+	}
+	// Key wasn't found. We fall back to the default case.
+	return string(buf), nil
 }
 
 func (StringMap) ImplementsGraphQLType(name string) bool {