`useEffect` is not cleaning itself up on re-renders

[aeisenberg]

There are two uses of react's useEffect that are not properly calling its cleanup functions. See

vscode-codeql/extensions/ql-vscode/src/view/compare/Compare.tsx

Line 33 in 5658030

useEffect(() => {

and

vscode-codeql/extensions/ql-vscode/src/view/remote-queries/RemoteQueries.tsx

Line 397 in 5658030

useEffect(() => {

useEffect docs https://reactjs.org/docs/hooks-reference.html#useeffect.

Discovered in #1578