[frontend] fix Sightings tab under Observables and Indicators (#8814)

[CelineSebe]

Proposed changes

• isTo become false in the sightings indicator and observables

Related issues

• Sightings tab under Observables and Indicators shows no data #8814

Checklist

• I consider the submitted work as finished
• I tested the code for its functionality
• I wrote test cases for the relevant uses case (coverage and e2e)
• I added/update the relevant documentation (either on github or on notion)
• Where necessary I refactored code to improve the overall quality

Further comments

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 65.48%. Comparing base (d47dbae) to head (d444213).
Report is 28 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #9486      +/-   ##
==========================================
+ Coverage   65.34%   65.48%   +0.13%     
==========================================
  Files         624      628       +4     
  Lines       59697    60313     +616     
  Branches     6685     6943     +258     
==========================================
+ Hits        39010    39494     +484     
- Misses      20687    20819     +132     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[marieflorescontact]

when I create a sighting from organization, then click on the created sighting i'm redirected to the indicator knowledge tab and sighting is in sighting tab 👌. is that correct?
Don't we want to be redirected to /dashboard/events/sightings/{sighting_id}. as commented in the issue:
#8146
if it's ok to be redirected to the entity's knowlede page then it works fine.