environment: Remove inline import of extensionUtils

The logging function cannot be asynchronous, so move the override
into main.js where ExtensionUtils can be imported at the top level.
Importing ExtensionUtils in environment.js at the top level is not
possible because it would import Main prematurely.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2363>

js/ui/main.js

@@ -141,7 +141,27 @@ function _sessionUpdated() {
     }
 }
 
+/**
+ * @param {any...} args a list of values to log
+ */
+function _loggingFunc(...args) {
+    let fields = { 'MESSAGE': args.join(', ') };
+    let domain = 'GNOME Shell';
+
+    // If the caller is an extension, add it as metadata
+    let extension = imports.misc.extensionUtils.getCurrentExtension();
+    if (extension != null) {
+        domain = extension.metadata.name;
+        fields['GNOME_SHELL_EXTENSION_UUID'] = extension.uuid;
+        fields['GNOME_SHELL_EXTENSION_NAME'] = extension.metadata.name;
+    }
+
+    GLib.log_structured(domain, GLib.LogLevelFlags.LEVEL_MESSAGE, fields);
+}
+
 function start() {
+    globalThis.log = _loggingFunc;
+
     // These are here so we don't break compatibility.
     global.logError = globalThis.log;
     global.log = globalThis.log;