Cleanup img-src attributes in the CSP directive

By restricting `img-src` in our CSP, we weren't allowing images from
e.g. https://github.com like CI badges to display.

With this change we allow users to add images from any `https`, `data`
or `blob` source, which is more user friendly.

crates/radicle-tauri/tauri.conf.json

@@ -21,7 +21,7 @@
       "csp": {
         "default-src": "'self'",
         "connect-src": "ipc: http://ipc.localhost",
-        "img-src": "'self' asset: http://asset.localhost blob: data:",
+        "img-src": "'self' blob: data: https:",
         "style-src": "'unsafe-inline' 'self'"
       },
       "pattern": {