Compose buffer resizes after increasing it's height

### OS/platform

Linux

### Emacs version and provenance

31.x

### Emacs command

emacs --fg-daemon

### Emacs frame type

X

### Ement package version and provenance

latest master

### Actions taken

1. C-'
2. Resize window
3. Type
4. Window size is reduced.

### Observed results

When trying to use compose buffer I like to increase its height beyond the default sometimes.
After doing that and then typing the size is reduced again after a while.

### Expected results

That it doesn't go below the size I changed the compose buffer into.

### Backtrace

```elisp

```

### Etc.

_No response_