(core) Fix choice/ref list cell color not filling cell

Summary:
This fixes the cell color only applying to the content height of a
choice or reference list cell, and not the entire cell. Could
be reproduced by causing a row other than the choice/reference
list to grow in height.

Test Plan: Tested manually.

Reviewers: dsagal

Reviewed By: dsagal

Subscribers: dsagal

Differential Revision: https://phab.getgrist.com/D3226

app/client/widgets/ChoiceListCell.ts

@@ -51,11 +51,11 @@ export class ChoiceListCell extends ChoiceTextBox {
 
 export const cssChoiceList = styled('div', `
   display: flex;
+  align-content: start;
   align-items: start;
   padding: 0 3px;
 
   position: relative;
-  height: min-content;
   min-height: 22px;
 
   &-wrap {