fix: img-src annotation changes with zui move to vite (#3539)

https://github.com/project-zot/zui/pull/484

zui is moving to vite framework but there are some changes in the
img-src annotations which must be allowed/accounted for in zot backend.

Signed-off-by: Ramkumar Chinchani <rchincha.dev@gmail.com>

pkg/extensions/extension_ui.go

@@ -50,7 +50,7 @@ func addUISecurityHeaders(h http.Handler) http.HandlerFunc { //nolint:varnamelen
 			"style-src 'self' 'unsafe-inline'",
 			"font-src 'self'",
 			"connect-src 'self'",
-			"img-src 'self'",
+			"img-src 'self' data:",
 			"manifest-src 'self'",
 			"base-uri 'self'",
 		}