fix: multiframe image prefetch logic

[slak44]

When the StudyPrefetcher is enabled, it prefetches the images of the current stack (and a prop is passed to react-cornerstone-viewport to stop it from prefetching).

Unfortunately, the code in StudyPrefetcher that computed which imageIds should be fetched was broken for multiframe images. As a result, nothing except the current image got loaded (triggering a load on every stack scroll, which is not great).

The first issue was that StudyPrefetcher used a non existent property numFrames, which made it think all images have a single frame (undefined > 1 is false).
The second issue was that the getImageId standalone function delegates to InstanceMetadata#getImageId, but without passing along its arguments (the frame argument, in particular).
The third issue was that InstanceMetadata#getImageId cached its return value, but that's not ok to do when the frame argument can vary.

[codecov]

Codecov Report

Merging #3097 (1a86208) into master (fe57c00) will decrease coverage by 0.73%.
The diff coverage is 2.05%.

@@            Coverage Diff             @@
##           master    #3097      +/-   ##
==========================================
- Coverage   12.68%   11.94%   -0.74%     
==========================================
  Files         306      306              
  Lines        8233     8437     +204     
  Branches     1593     1679      +86     
==========================================
- Hits         1044     1008      -36     
- Misses       5797     5942     +145     
- Partials     1392     1487      +95     

Impacted Files	Coverage Δ
...latform/core/src/DICOMSR/SCOORD3D/parseSCOORD3D.js	2.66% <0.00%> (-0.73%)	⬇️
.../core/src/DICOMSR/SCOORD3D/utils/addMeasurement.js	5.40% <ø> (ø)
...re/src/DICOMSR/SCOORD3D/utils/getRenderableData.js	1.72% <0.00%> (-0.07%)	⬇️
...orm/core/src/DICOMSR/parseDicomStructuredReport.js	7.50% <0.00%> (-1.60%)	⬇️
platform/core/src/classes/HotkeysManager.js	76.66% <0.00%> (ø)
platform/core/src/classes/StudyLoadingListener.js	1.03% <0.00%> (+0.01%)	⬆️
platform/core/src/classes/StudyPrefetcher.js	0.69% <0.00%> (ø)
.../core/src/classes/metadata/OHIFInstanceMetadata.js	0.00% <0.00%> (ø)
...latform/core/src/classes/metadata/StudyMetadata.js	1.25% <0.00%> (-0.04%)	⬇️
.../core/src/measurements/tools/dicomSRDisplayTool.js	50.00% <0.00%> (ø)
... and 28 more

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[sedghi]

base has changed, read more here #3477