Closes#2574
cc @SuaYoo
## Changes
This adds an internal `--btrix-table-grid-template-columns--internal`
css property to `btrix-table` to set table grid cols, which uses the
`--btrix-table-grid-template-columns` value if defined and otherwise
defaults to the number of header cols **from within the css
declaration**, rather than using JS. In Chrome at least,
`this.style.getPropertyValue` wasn't picking up on css variables defined
outside of the custom component boundary, so this gets around that.
Other changes:
- Adds an additional column to the superadmin org list, as it was
missing one
- Fixes `overflow-dropdown` unintentionally setting its internal
button's size to `undefined` if `size` wasn't set on it
- Swaps the remaining tables to use
`--btrix-table-grid-template-columns` instead of directly setting
`grid-template-columns`
- Adds a min-width of `min-content` to the table container, because
doing so is necessary for left/right scrolling, and this is a common
enough pattern it seems that upstreaming this into the table itself
makes sense — it shouldn't cause breakages, this already generally is
the expected behaviour
- Allows tables to scroll left/right when necessary
- Fix padding/margin for a few left/right scrolling tables
- Allows primary column of collections list to shrink to a smaller min
width
## Testing
Test that none of the other tables are broken. I couldn't find any!
8a707e3b3a