Add pagination logic to fetch all timeline events

Created by: eseliger

Fixes values derived from events on busy PRs by using the pagination info from GraphQL to receive all pages of items. This happens when a PR has a lot of comments or a lot of commits in it, and this should ultimately fix it. I think we don't need to worry about running into rate limits, because it only happens to have so many events very rarely. (But it happened on our own repo!)

Closes #11744

Created by: codecov[bot]

Codecov Report

Merging #14525 into main will increase coverage by 0.00%. The diff coverage is 58.57%.

@@           Coverage Diff           @@
##             main   #14525   +/-   ##
=======================================
  Coverage   52.26%   52.26%           
=======================================
  Files        1555     1555           
  Lines       79081    79138   +57     
  Branches     7053     7053           
=======================================
+ Hits        41329    41360   +31     
- Misses      34028    34046   +18     
- Partials     3724     3732    +8     

Flag	Coverage Δ
#go	52.55% <58.57%> (+<0.01%)
#integration	30.81% <ø> (ø)
#storybook	21.85% <ø> (ø)
#typescript	51.56% <ø> (ø)
#unit	33.60% <ø> (ø)

Impacted Files	Coverage Δ
internal/extsvc/github/pulls.go	58.52% <58.57%> (+0.25%)
.../internal/codeintel/resolvers/graphql/locations.go	83.50% <0.00%> (-2.07%)
cmd/frontend/graphqlbackend/zoekt.go	74.80% <0.00%> (-0.51%)
...codeintel/bundles/persistence/cache/store_cache.go	93.58% <0.00%> (+1.28%)