Using ${var} in strings is deprecated, use {$var} instead

@_pratik_ Thanks for creating patch.
Patch working fine as per the issue summary.
Please create MR as per your patch.
Thanks

Deprecated: Using ${var} in strings is deprecated, use {$var} instead in [...]/web/themes/contrib/thunder_admin/thunder_admin.theme on line 352
The website encountered an unexpected error. Please try again later.
RuntimeException: Failed to start the session because headers have already been sent by "[...]/web/themes/contrib/thunder_admin/thunder_admin.theme" at line 352. in Symfony\Component\HttpFoundation\Session\Storage\NativeSessionStorage->start() (line 132 of [...]/vendor/symfony/http-foundation/Session/Storage/NativeSessionStorage.php).

Drupal 10.1.2, Thunder Admin 4.0.5, Seven 1.0.0 (D7-D10 upgraded[migrated] site)

Sorry, I'm not at the level to patch anything myself :-)

cntr-r lets go, but annoying...

Patched Drupal 10.2.6 on PHP8.3 with MR8 and phpstan stopped reporting on this issue.