Add props for min-width for OuiModal

[curq]

Is your feature request related to a problem? Please describe.

OuiModal currently only supports the max-width property and not min-width. It is useful property that might be necessary for some layouts.

Describe the solution you'd like

Add min-width property for OuiModal. It should be similar to max-width that is already supported.

Describe alternatives you've considered

Using custom styling when min-width is required, but it is not preferred as it is better experience to keep it within component logic without making extra styles just for one property.

Additional context

This gap was identified in following OUI compliance audit:

• [Research] [CCI] OUI Usage Audit in console plugin OpenSearch-Dashboards#3966
• [Research] OUI Compliance audit of the saved_objects plugin OpenSearch-Dashboards#4161

[joshuarrrr]

@KrooshalUX Can you weigh in here? We've seen at least a couple plugins that attempt to do this, but I'm not sure if we actually prefer a minimum width property.

[joshuarrrr]

OK, I've looked at the two usages we've found so far, and I think they both demonstrate that min-width or width are not necessary (YAGNI).

In saved_objects the style is fixing the modal width at a value that's already the default size:

Screen.Recording.2023-06-08.at.5.29.10.PM.mov

In console, the difference is negligible.

Screen.Recording.2023-06-08.at.5.27.28.PM.mov

So neither of these cases demonstrate a real need for width properties, but @KrooshalUX can weigh in on the perspective of whether designers will need this low-level control or not.

[joshuarrrr]

I propose moving a bit in the opposite direction and making the autosizing behavior the guidance: #803