MM-58275 Ensure image proxy site URL is updated when that changes (#27214)

* MM-58275 Ensure image proxy site URL is updated when that changes

* Check if proxy settings changed using reflection

server/platform/services/imageproxy/atmos_camo_test.go

@@ -66,14 +66,13 @@ func TestAtmosCamoBackend_GetImageDirect(t *testing.T) {
 	defer mock.Close()
 
 	proxy := makeTestAtmosCamoProxy()
-	parsedURL, err := url.Parse(*proxy.ConfigService.Config().ServiceSettings.SiteURL)
+	parsedURL, err := url.Parse("https://mattermost.example.com")
 	require.NoError(t, err)
 
 	remoteURL, err := url.Parse(mock.URL)
 	require.NoError(t, err)
 
 	backend := &AtmosCamoBackend{
-		proxy:     proxy,
 		siteURL:   parsedURL,
 		remoteURL: remoteURL,
 		client:    proxy.HTTPService.MakeClient(false),
@@ -177,9 +176,9 @@ func TestGetAtmosCamoImageURL(t *testing.T) {
 			require.NoError(t, err)
 
 			backend := &AtmosCamoBackend{
-				proxy:     makeTestAtmosCamoProxy(),
-				siteURL:   parsedURL,
-				remoteURL: remoteURL,
+				siteURL:       parsedURL,
+				remoteURL:     remoteURL,
+				remoteOptions: *makeTestAtmosCamoProxy().ConfigService.Config().ImageProxySettings.RemoteImageProxyOptions,
 			}
 
 			assert.Equal(t, test.Expected, backend.getAtmosCamoImageURL(test.Input))