Refactor FormattedDropdown and enhance BranchView functionality

- Updated the FormattedDropdown component to use normal document flow for the dropdown list, ensuring visibility when opened.
- Enhanced the createBranch method in BranchView to automatically select the most recently created branch after a new branch is added, improving user experience.

frontend/src/views/falukant/BranchView.vue

@@ -148,6 +148,17 @@ export default {
 
         async createBranch() {
             await this.loadBranches();
+            // Nach dem Anlegen eines neuen Branches automatisch den
+            // zuletzt/neu erstellten Branch auswählen.
+            if (this.branches.length > 0) {
+                const newest = this.branches.reduce((acc, b) =>
+                    !acc || b.id > acc.id ? b : acc,
+                    null
+                );
+                if (newest) {
+                    await this.onBranchSelected(newest);
+                }
+            }
         },
 
         upgradeBranch() {