[SIEM][Detection Engine] Closing of signals does not update count correctly on the signals table

[FrankHassanabad]

See gif below, when using SIEM signals you can close signals and the count does not consistently update. Below you can see it did not subtract 3 closed signals from the count when it should have:

Steps to reproduce:

1. Create signals by adding some rules such as 'host.name: *'
2. Run the rule for a few minutes and shut it down so you have signals
3. Go the signals table and refresh your web page
4. Click to close 3 signals and see if it updates the count or not. If does update the count, do it a few more times until you see it not work correctly.

** Workaround **
Refresh your page

Expected behavior:
It should always update the count correctly when you close signals.

Kibana version:
7.6.1, 7.x, master

Elasticsearch version:
7.6.1, 7.x, master

Server OS version:
Cloud

Browser version:
Chrome 80+

Browser OS version:
Chrome 80+

Original install method (e.g. download page, yum, from source, etc.):
cloud

[elasticmachine]

Pinging @elastic/siem (Team:SIEM)

[FrankHassanabad]

This has been fixed by other work involving wait_for and timeline table fixes generically.