Re-enable `useUnknownInCatchVariables`

[dkundel]

TypeScript v4.4 changed the type of errors caught in a catch clause to be unknown as opposed to any. In order to ease the transition from v3 to v4 we turned this off in #450. Ideally we should enable this again for better type checking. This requires the following changes:

1. Turn on useUnknownInCatchVariables in the tsconfig.base.json
2. Run npm run build and see which files fail.
3. Add type guards to convert unknown to the right relevant type and handle cases where it's a different type
4. Re-run npm run build to validate that everything compiles correctly.

To do a more iterative approach you can also enable useUnknownInCatchVariables inside each individual tsconfig.json in the respective packages first before enabling it entirely.