MM-16474: SMTP password should be redacted in system console. (#11350)

Fix Santize function to be the opposite of the Desanitize function for
the config file, and add a unit test for Sanitize.

model/config_test.go

@@ -916,3 +916,28 @@ func TestLdapSettingsIsValid(t *testing.T) {
 		})
 	}
 }
+
+func TestConfigSanitize(t *testing.T) {
+	c := Config{}
+	c.SetDefaults()
+
+	*c.LdapSettings.BindPassword = "foo"
+	*c.FileSettings.AmazonS3SecretAccessKey = "bar"
+	*c.EmailSettings.SMTPPassword = "baz"
+	*c.GitLabSettings.Secret = "bingo"
+	c.SqlSettings.DataSourceReplicas = []string{"stuff"}
+	c.SqlSettings.DataSourceSearchReplicas = []string{"stuff"}
+
+	c.Sanitize()
+
+	assert.Equal(t, FAKE_SETTING, *c.LdapSettings.BindPassword)
+	assert.Equal(t, FAKE_SETTING, *c.FileSettings.PublicLinkSalt)
+	assert.Equal(t, FAKE_SETTING, *c.FileSettings.AmazonS3SecretAccessKey)
+	assert.Equal(t, FAKE_SETTING, *c.EmailSettings.SMTPPassword)
+	assert.Equal(t, FAKE_SETTING, *c.GitLabSettings.Secret)
+	assert.Equal(t, FAKE_SETTING, *c.SqlSettings.DataSource)
+	assert.Equal(t, FAKE_SETTING, *c.SqlSettings.AtRestEncryptKey)
+	assert.Equal(t, FAKE_SETTING, *c.ElasticsearchSettings.Password)
+	assert.Equal(t, FAKE_SETTING, c.SqlSettings.DataSourceReplicas[0])
+	assert.Equal(t, FAKE_SETTING, c.SqlSettings.DataSourceSearchReplicas[0])
+}