Revert "fix(ui): allow manual prompt bar resize (#1201)"

This reverts commit 258e6fc0d4.

tests/test_prompt_bar_manual_resize.py

@@ -1,16 +0,0 @@
-from pathlib import Path
-
-
-CSS = Path("static/style.css").read_text(encoding="utf-8")
-UI_JS = Path("static/js/ui.js").read_text(encoding="utf-8")
-
-
-def test_prompt_bar_exposes_desktop_resize_handle():
-    assert "resize: vertical;" in CSS
-    assert "max-height: min(60vh, 600px);" in CSS
-
-
-def test_auto_resize_preserves_a_manually_chosen_height():
-    assert "textarea._manualResizeHeight = height;" in UI_JS
-    assert "const manualHeight = textarea._manualResizeHeight || 0;" in UI_JS
-    assert "const maxHeight = Math.max(autoMaxHeight, manualHeight);" in UI_JS