Fatal exception when setting a notification as not read

[jonasraoni]

Describe the bug It's not possible to mark notifications as not read.

Updating the NotificationDAO::setDateRead() to accept null dates, should do it.

To Reproduce Steps to reproduce the behavior:

1. Select a notification at the top menu
2. Click on "Mark New"
3. See error

What application are you using? OJS 3.4

[taslangraham]

Ready for review @jonasraoni

PRs:

pk-lib (3_4_0) - https://github.com/pkp/pkp-lib/pull/10224 pkp-lib (main) - https://github.com/pkp/pkp-lib/pull/10225

submodule updates: ojs (3_4_0) - https://github.com/pkp/ojs/pull/4371 ojs (main) - https://github.com/pkp/ojs/pull/4372 omp (3_4_0) - https://github.com/pkp/omp/pull/1648 omp (main) - https://github.com/pkp/omp/pull/1649 ops (3_4_0) - https://github.com/pkp/ops/pull/734 ops(main) - https://github.com/pkp/ops/pull/735

[jonasraoni]

@taslangraham I've merged the PRs for the pkp-lib and closed the others (there are some conflicts).

If our policy hasn't changed (remind me to confirm this on the next call), we're not merging very often PRs that just update the submodule, to avoid creating such merge conflicts.