Resolve flaky timer test

[remcowesterhoud]

Description

We are not entirely sure what the cause of the flakyness is, however by improving the assertions to be more specific to what this test is supposed to fix we expect that the flakyness is resolved.

Related issues

closes #10272

Definition of Done

Not all items need to be done depending on the issue and the pull request.

Code changes:

• The changes are backwards compatibility with previous versions
• If it fixes a bug then PRs are created to backport the fix to the last two minor versions. You can trigger a backport by assigning labels (e.g. backport stable/1.3) to the PR, in case that fails you need to create backports manually.

Testing:

• There are unit/integration tests that verify all acceptance criterias of the issue
• New tests are written to ensure backwards compatibility with further versions
• The behavior is tested manually
• The change has been verified by a QA run
• The impact of the changes is verified by a benchmark

Documentation:

• The documentation is updated (e.g. BPMN reference, configuration, examples, get-started guides, etc.)
• If the PR changes how BPMN processes are validated (e.g. support new BPMN element) then the Camunda modeling team should be informed to adjust the BPMN linting.

Please refer to our review guidelines.

[github-actions]

Test Results

   957 files  ±  0     957 suites  ±0   1h 41m 26s ⏱️ - 1m 50s
7 636 tests  - 55  7 629 ✔️  - 55  7 💤 ±0  0 ❌ ±0 
7 836 runs   - 55  7 827 ✔️  - 55  9 💤 ±0  0 ❌ ±0 

Results for commit 3ca46f0. ± Comparison against base commit 929988c.

[koevskinikola]

lgtm 🚀

bors merge

[zeebe-bors-camunda]

Build succeeded:

• Test summary

[backport-action]

Successfully created backport PR #11051 for stable/8.0.

[backport-action]

Successfully created backport PR #11052 for stable/8.1.