TextEdit::clip_text is being ignored for singleline text

[Barugon]

Describe the bug
TextEdit::clip_text is being ignored for singleline text. With clip_text set to true, the TextEdit widget expands when the text gets too long.

Here are a couple screenshots showing the behavior.

Before adding text:

Pasting in some long text:

If I maximize the window (also odd behavior since I have window resizing disabled) then you can see the full size of the TextEdit:

This behavior started with v0.30 and still exists in the main branch.

[edit] This may be related to #5500.