Terminal toolbar overlaps panel tabs and clicks select the tabs underneath

Does this issue occur when all extensions are disabled?: Yes

- VS Code Version: 1.136.1
- OS Version: Windows_NT x64 10.0.26200

### Description
The integrated terminal toolbar overlaps other tabs in the panel header. The New Terminal (+) button and other overlapping toolbar buttons are visible on top of the tabs, but hovering over or clicking them targets the tab underneath instead. This prevents creating a terminal using the New Terminal button in the affected layout.

### Steps to Reproduce
1. Open the integrated Terminal panel.
2. With the panel header in the overlapping layout shown in the screenshot, hover over the New Terminal (+) button or another toolbar button that overlaps a panel tab.
3. Click the overlapping button.

The exact conditions that initially cause the overlap have not yet been isolated. These steps describe the interaction once the overlapping layout is present.

### Expected Behavior
The terminal toolbar and panel tabs should not overlap. Hovering over a toolbar button should target that button, and clicking New Terminal should create a terminal.

### Actual Behavior
Toolbar controls are drawn over the panel tabs, but their hover and click interactions are ignored. Clicking a visible toolbar button selects the tab underneath instead.

### Screenshot

### Additional Information
- Reproduction in the latest Insiders build: not yet tested.
- Potentially related report: #334923 (terminal cwd label overlaps panel tabs). It has not been confirmed whether this is the same underlying issue.