Regenerate the client id / first run date if needed

[Dexterp37]

Old builds of products using glean, which were already executed once, once updated, might not correctly report the client id and the first run date. Since these are likely low number of developer builds, we simply regenerate these fields.

Pull Request checklist

• Quality: This PR builds and passes detekt/ktlint checks (A pre-push hook is recommended)
• Tests: This PR includes thorough tests or an explanation of why it does not
• Changelog: This PR includes a changelog entry or does not need one
• Accessibility: The code in this PR follows accessibility best practices or does not include any user facing features

[codecov]

Codecov Report

Merging #2723 into master will increase coverage by 0.16%.
The diff coverage is 90%.

@@             Coverage Diff              @@
##             master    #2723      +/-   ##
============================================
+ Coverage     82.69%   82.86%   +0.16%     
- Complexity     2885     2911      +26     
============================================
  Files           359      365       +6     
  Lines         12260    12403     +143     
  Branches       1797     1810      +13     
============================================
+ Hits          10139    10278     +139     
- Misses         1379     1382       +3     
- Partials        742      743       +1

Impacted Files	Coverage Δ	Complexity Δ
...ain/java/mozilla/components/service/glean/Glean.kt	94.23% <90%> (+1.37%)	1 <0> (ø)	⬇️
...omponents/service/glean/private/EventMetricType.kt	85.29% <0%> (-0.92%)	16% <0%> (ø)
...ents/service/glean/storages/EventsStorageEngine.kt	84.21% <0%> (-0.88%)	25% <0%> (ø)
...components/service/glean/private/UuidMetricType.kt	91.66% <0%> (-0.34%)	15% <0%> (-1%)
...ponents/feature/tabs/toolbar/TabsToolbarFeature.kt	100% <0%> (ø)	2% <0%> (?)
...la/components/feature/tabs/tabstray/TabsFeature.kt	100% <0%> (ø)	6% <0%> (?)
...ponents/feature/tabs/tabstray/TabsTrayPresenter.kt	97.56% <0%> (ø)	11% <0%> (?)
...onents/feature/tabs/tabstray/TabsTrayInteractor.kt	100% <0%> (ø)	5% <0%> (?)
...ts/feature/tabs/toolbar/TabCounterToolbarButton.kt	90.47% <0%> (ø)	2% <0%> (?)
...va/mozilla/components/feature/tabs/TabsUseCases.kt	100% <0%> (ø)	1% <0%> (?)

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[travis79]

r+ (Do we have/should we file) a bug to look at this again in 6 months to remove the cruft (after it's hopefully no longer needed)?

[mdboom]

LGTM. My comment is more just thinking out loud, and not a requirement to merge this.

[mdboom]

Random thought -- we could record an error on the metric here so we could see how often this happens. If it shows up again in the future, it might help us detect mistakes...

[travis79]

Ooh, I like this idea!

[Dexterp37]

Yeah, that might be a good idea. The thing is that, in contrast to desktop, we have no alerting on this for now. It it would be up to humans (that's us!) to manually check in that for now. I'd rather have a monitor or alerting on schema validation errors (that caught this!!!!), which is a lower hanging fruit with the tooling that's available right now. Additionally, I'm planning on prioritizing the integration test.

[Dexterp37]

r+ (Do we have/should we file) a bug to look at this again in 6 months to remove the cruft (after it's hopefully no longer needed)?

I filed this https://bugzilla.mozilla.org/show_bug.cgi?id=1543979