MM-63411 Don't focus thread textbox automatically when it has a draft (#31250)

* MM-63411 Don't focus thread textbox automatically when it has a draft

* Add E2E test

* Add test files forgotten in previous commit

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Co-authored-by: Mattermost Build <build@mattermost.com>

webapp/channels/src/components/advanced_text_editor/advanced_text_editor.tsx

@@ -523,7 +523,7 @@ const AdvancedTextEditor = ({
     // Update the caret position in the input box when changed by a side effect
     useEffect(() => {
         const textbox: HTMLInputElement | HTMLTextAreaElement | undefined = textboxRef.current?.getInputBox();
-        if (textbox && textbox.selectionStart !== caretPosition) {
+        if (textbox && textbox === document.activeElement && textbox.selectionStart !== caretPosition) {
             Utils.setCaretPosition(textbox, caretPosition);
         }
     }, [caretPosition]);