fix(images): correct mifos logo reference from png to jpg (#2959)

Correct incorrect references to `mifos_lg-logo.png`.

The PNG asset does not exist; the correct file is `mifos_lg-logo.jpg`.
Although the UI rendered correctly due to fallback logic, the incorrect
reference was misleading and could cause issues in future refactors.

src/theme/_dark_content.scss

@@ -271,7 +271,7 @@ body.dark-theme {
 
   // Home page logo styling for dark mode
   mifosx-home {
-    [src*='mifos_lg-logo.png'],
+    [src*='mifos_lg-logo.jpg'],
     [src$='_home.png'] {
       content: url('../assets/images/white-mifos.png');
     }