fractal-matrix-api: Add workaround for synapse bug 4898

Synapse has a bug that can cause 'ts' for read receipts
to be malformed: https://github.com/matrix-org/synapse/issues/4898

This sets a workaround by replacing the malformed timestamp
to be replaced with 0.

Closes GNOME/fractal#472
4 jobs for <span class="ref-name">wip/christopherdavis/workaround-synapse-4898</span> in 22 minutes and 29 seconds (queued for 5 minutes and 50 seconds)
Status Job ID Name Coverage
  Check
passed #266553
check

00:03:15

 
  Test
passed #266554
flatpak

00:18:15

 
  Review
passed #266555
review

00:00:29

failed #266556
allowed to fail manual
stop_review

00:00:29

 
Name Stage Failure
failed
stop_review Review
From https://gitlab.gnome.org/BrainBlasted/fractal
* [new branch] master -> origin/master
* [new branch] room_member_events -> origin/room_member_events
* [new branch] wip/christopherdavis/fit-room-directory -> origin/wip/christopherdavis/fit-room-directory
* [new branch] wip/christopherdavis/redesign-login-flow -> origin/wip/christopherdavis/redesign-login-flow
* [new tag] 0.1.0 -> 0.1.0
Checking out 8c97771d as wip/christopherdavis/workaround-synapse-4898...
fatal: reference is not a tree: 8c97771dab6914cef3eec818d775e24d9b18badb
ERROR: Job failed: exit code 1