Feat/auto copy lobby code (#3758)

Resolves #3757

## Description:

Simple patch that would remove an extra click that users have to do each
time they create a private lobby. On top of the existing button, the
game link will automatically be copied to the clipboard when clicking
"Create Lobby".


## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

zixer._

src/client/components/CopyButton.ts

@@ -80,7 +80,7 @@ export class CopyButton extends LitElement {
     return await this.buildCopyUrl();
   }
 
-  private async handleCopy() {
+  async handleCopy() {
     const text = await this.resolveCopyText();
     if (!text) {
       alert("Error copying game id");