Allow buttons to grow and wrap with long or multi-line content

[lacatoire]

Fixes #7303.

Buttons used a fixed block-size and min-inline-size: max-content, which clipped multi-line or long labels and broke the .text-wrap utility. Switching to min-block-size lets buttons grow vertically while preserving the default height for single-line content, and removing min-inline-size: max-content lets .text-wrap actually wrap the label inside tight containers.

Three CSS lines changed in assets/css/easyadmin-theme/buttons.css:

• .btn: block-size -> min-block-size, drop min-inline-size: max-content
• .btn-lg: block-size -> min-block-size

Regression checks performed locally with Chromium:

• Default, sm and lg buttons keep their previous heights (32/28/40 px) for short single-line labels.
• Icon-only buttons render unchanged.
• Multi-line labels (with <br>) now fit inside the button instead of being clipped.
• .text-wrap now wraps the label and grows the button vertically, as intended.