[BUG]: Selecting text right-to-left causes the next character input to be dropped in Firefox

### Describe the bug

Selecting text right-to-left causes the next character input to be dropped in Firefox. Selecting text left-to-right and typing works as expected. Non-character inputs such as delete, backspace, or page down work fine.

I cannot reproduce the issue in chrome, and I've disabled my extensions to make sure they're not interfering with the page somehow.

### Steps to reproduce

1. Visit godbolt.org
2. Select any language to load example code
3. Highlight some code starting from the right and dragging the mouse cursor left
4. Press any character - nothing happens
5. Press any character - the selected text is replaced with the character

This also happens if you select text with the keyboard using shift+home or shift+left instead of using the mouse. Shift+end and shift+right works as expected.

### Expected behavior

When you type, the selected text should always be replaced with the character you typed.

### Reproduction link

Not applicable

### Screenshots

Not applicable

### Operating System

Windows 11

### Browser version

Firefox 151.0.2

Start by reproducing the selection and typing steps on godbolt.org in Firefox, comparing right-to-left and left-to-right selection with mouse and keyboard. Trace the page's text-input and selection handling to find where the first character is dropped; done means the first character replaces the selected text in each listed case without changing the working behavior.

Written by the indexing model from the issue text.