[keyserver][web] Refactor getInitialReduxState action
Summary: issue: https://linear.app/comm/issue/ENG-5181/refactor-getinitialreduxstate-action
Test Plan: Checked that the value returned by this action is correct, chekced that the app loads without errors
Reviewers: michal, kamil, ginsu
Reviewed By: michal
Subscribers: ashoat, tomek, wyilio
Differential Revision: https://phab.comm.dev/D9650