graphing/designer: keep each config table's collapse state

Switching tabs remounted both tables, so every row came back collapsed -
along with the drafts a row editor holds, which cannot be read back out
of the store. Keep the panels mounted instead; the appearance table now
opens the rows that fan out into lines.

Per-row state is pruned as rows disappear: nextId reissues a freed id, so
a new row used to inherit the deleted row's expansion and selection.
reka-ui activates a tab on mousedown, hence userEvent in the tests.

Change-Id: I78f851d8cda85004e801203fa08433498b101c2a
JIRA-Ref: CMK-38111