fix(theming): use IAppConfig instead of IConfig to set theming config

Signed-off-by: Salvatore Martire <4652631+salmart-dev@users.noreply.github.com>

apps/theming/lib/ThemingDefaults.php

@@ -432,7 +432,7 @@ class ThemingDefaults extends \OC_Defaults {
 	 * @param string $value
 	 */
 	public function set($setting, $value): void {
-		$this->config->setAppValue('theming', $setting, $value);
+		$this->appConfig->setValueString('theming', $setting, $value);
 		$this->increaseCacheBuster();
 	}
 

apps/theming/tests/ThemingDefaultsTest.php

@@ -500,18 +500,14 @@ class ThemingDefaultsTest extends TestCase {
 	}
 
 	public function testSet(): void {
-		$expectedCalls = [
-			['theming', 'MySetting', 'MyValue'],
-			['theming', 'cachebuster', 16],
-		];
-		$i = 0;
 		$this->config
-			->expects($this->exactly(2))
+			->expects($this->once())
 			->method('setAppValue')
-			->willReturnCallback(function () use ($expectedCalls, &$i): void {
-				$this->assertEquals($expectedCalls[$i], func_get_args());
-				$i++;
-			});
+			->with('theming', 'cachebuster', 16);
+		$this->appConfig
+			->expects($this->once())
+			->method('setValueString')
+			->with('theming', 'MySetting', 'MyValue');
 		$this->config
 			->expects($this->once())
 			->method('getAppValue')