fix: prevent double-tap-drag zoom gesture emitting a tap event

[androidseb]

This change fixes a minor bug in the gesture system: when initiating a double-tap-drag-zoom gesture, a tap on the map would be registered through the MapOptions.onTap callback.

[androidseb]

I tested this on mobile and web and it seems to work well, marking this as ready for review now.

[josxha]

Sorry I haven't had time to record the videos earlier. I was able to reproduce the following bug on the master branch (pre merge):
After a double tap drag zoom gesture the next tap or double tap drag zoom gesture calls the onTap callback twice and emits two MapEventTap events. However i have doubts that this PR fixes this bug because I was able to reproduce it on the PR branch too.

master branch	pull request
flutter_map.master.2.Mit.Clipchamp.erstellt.mp4	flutter.map.pr.Mit.Clipchamp.erstellt.mp4

And here is a showcase when performing a double tap drag zoom gesture and tap gesture afterwards using the pull request branch:

Bug_.onTap.callbacks.called.twice.Mit.Clipchamp.erstellt.1.mp4

[androidseb]

@josxha thanks for finding those issues, I looked at your videos and tried to reproduce the problem on my computer - it took me a lot of tries to actually notice the problem because it was random:

• On the master branch: the bug happens 100% of the time
• On the PR branch (before it was reverted): it happens very randomly - sometimes I can perform the gesture 10 times in a row without problem, and sometimes after just 2 gestures it will send the duplicate onTap event

Were you also experiencing this randomness on your machine?

[JaffaKetchup]

(After retesting, I could reproduce without randomness as far as I could see.)

This PR has been reverted by #1799.

[josxha]

I had some struggle to reproduce it too every time, sometimes i even messed up because I failed to perform the double tap drag zoom gesture with my mouse. 😅
I believe it has some logic of when it occurs but couldn't tell what exactly.

FYI: There is an rewrite on the gesture system in #1733 that will get introduced with the next major flutter_map version (fingers crossed :D ). If you want you can check if the bug occurs there too, I tried it real quick and couldn't reproduce it on that branch.

[androidseb]

@josxha thanks for linking your PR here. This is a tricky problem for sure, I spent about an hour wrestling with the PositionedTapDetector2 class and almost got it to work, but couldn't get rid of the randomness in some edge cases.

I'll wait for your PR changes to land and I'll test those instead 👍

[JaffaKetchup]

(Just wanted to say thanks @androidseb (even if it didn't exactly go to plan this time), and my apologies for not testing correctly, I completely misread/remembered the gesture these changes applied to.)