light: add case to catch cancelled contexts within the detector (backport #6701)

[mergify]

This is an automatic backport of pull request #6701 done by Mergify.
Cherry-pick of 40fba39 has failed:

On branch mergify/bp/v0.34.x/pr-6701
Your branch is up to date with 'origin/v0.34.x'.

You are currently cherry-picking commit 40fba3960.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   light/client_test.go

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   light/detector.go
	both modified:   light/provider/mock/mock.go

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/github/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

---

Mergify commands and options

More conditions and actions can be found in the documentation.

You can also trigger Mergify actions by commenting on this pull request:

• @Mergifyio refresh will re-evaluate the rules
• @Mergifyio rebase will rebase this PR on its base branch
• @Mergifyio update will merge the base branch into this PR
• @Mergifyio backport <destination> will backport this PR on <destination> branch

Additionally, on Mergify dashboard you can:

• look at your merge queues
• generate the Mergify configuration with the config editor.

Finally, you can contact us on https://mergify.io/

[lgtm-com]

This pull request introduces 9 alerts when merging d678304 into da9eefd - view on LGTM.com

new alerts:

• 9 for Unreachable statement

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (v0.34.x@da9eefd). Click here to learn what that means.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             v0.34.x    #6720   +/-   ##
==========================================
  Coverage           ?   61.50%           
==========================================
  Files              ?      265           
  Lines              ?    27764           
  Branches           ?        0           
==========================================
  Hits               ?    17077           
  Misses             ?     9132           
  Partials           ?     1555           

[cmwaters]

Great work callum