[UEPR-380] ToU: Frontend blocking

[adzhindzhi]

Resolves:

UEPR-380

Changes:

There are currently two approaches in discussion: Display blocking modals vs. Display blocking pages

• The first commit completes the modal approach implementation, showing a blocking modal when opening the editor as well (the remaining was already implemented with the non-blocking ToU modals). This solution has a couple of drawbacks - it’s easier to bypass, can conflict with other modals, and currently lacks a logout option.
• The second commit reverts the modal implementation in favor of blocking pages. While this approach has some UX downsides, it is a bit more secure, harder to bypass, and supports logging out without additional work.

Test Coverage:

• Current test cases complete successfully

Page vs. Modal approach UI comparison: