fix(image-preview): prohibit triggering long press event when pinch zoom

[chouchouji]

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• prohibit triggering long press event when pinch zoom

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Name	Status	Preview	Comments	Updated (UTC)
varlet	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Aug 21, 2023 6:43am

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[codecov]

Codecov Report

Merging #1156 (d450b2f) into dev (cef0d36) will decrease coverage by 0.02%.
Report is 3 commits behind head on dev.
The diff coverage is 86.66%.

@@            Coverage Diff             @@
##              dev    #1156      +/-   ##
==========================================
- Coverage   95.74%   95.72%   -0.02%     
==========================================
  Files         337      337              
  Lines       22098    22104       +6     
  Branches     2180     2178       -2     
==========================================
+ Hits        21158    21160       +2     
- Misses        825      893      +68     
+ Partials      115       51      -64     

Files Changed	Coverage Δ
...kages/varlet-ui/src/image-preview/ImagePreview.vue	97.93% <86.66%> (-0.23%)	⬇️

... and 29 files with indirect coverage changes

[chouchouji]

I added the judgment of the number of touch points to fix this bug for the long press event.
In the next major version, I will refactor the logic here with reference to hammerjs
@haoziqaq