Make script list default wider, minimum narrower

[aXu-AP]

Give more space to the script lists by default, but makes minimum smaller than it was. Unifies script editor and shader editor to use same values.

Before

Here's how default&minimum value is in current master on 1080 resolution 100% editor scale:

Script editor: 150 px
Shader editor: 200 px
Note how script editor's list is so narrow that even new_script.gd(*) doesn't fit.

After

Here's the new default:

Script editor: 200 px
Shader editor: 200 px
Note how code editor is still 115 chars wide, enough for usual code (exceeding 100 chars hampers readability anyway, no matter how big of a monitor).

Here's the new minimum:

Script editor: 100 px
Shader editor: 100 px
As GUI doesn't break (altough it gets cramped), we shouldn't limit the user from customizing layout for small/portrait monitors.

Related: #96865 would benefit from this.

[Calinou]

The rationale makes sense to me, and code looks good.

[aXu-AP]

Is the mono check failing by some unrelated circumstance? Can I force it to rerun (amend something back and forth and force push the same commit?)

[tetrapod00]

Nice solution, I didn't know the default and the minimum could be split like that!

Edit: tested, and the script name truncation lacks ellipses at the minimum width, with default names (new_script.gd and new_shader.tres). Making it just one or two pixels wider fixes the problem. The ellipsis seems to appear at any width over 101 or 102. This is is probably an issue with the truncation code elsewhere, not specifically this PR.
Minimum, 100px:

Script editor at 101 or 102px, Shader editor at 100px:

godot.windows.editor.x86_64_gaLLMuQTjM.mp4

I can't reproduce this truncation behavior in 4.4dev2 with a minimum width of 150. So, it's existing behavior that is exposed by this PR. If you can find a fix great, otherwise this can be a separate issue/PR

[akien-mga]

Thanks!

[aXu-AP]

@tetrapod00 Sorry I didn't notice your edit. Could you open a separate issue for this so it won't be forgotten? Also check if it's editor specific or ItemList in general.

[tetrapod00]

@aXu-AP done in #97124