Modal doesn't resize in some cases

[grassick]

Go to portal.mwater.co/#datagrids

Pick Water Point, flip to filter tab. Then click on the box. It puts a scroll bar instead of making the modal bigger.

[broncha]

@grassick I just hit this too while working on expressions for ImageWidgetComponent.
This one is really tricky as the dropdown is absolutely positioned. I tested with bootstrap collapse and it stretches the modal body as expected.

Working on a fix for absolutely positioned elements.

[broncha]

The fix for scrolling modal body is a blocker to fix this one. We added overflow: auto to modal body which makes the dropdown to actually scroll. If we remove overflow:auto the dropdown will pop out of the modal.

[broncha]

After 29dd8d6. it looks like this