[ci] Avoid upload djl-serving.tar to S3 if already exist

[frankfliu]

Description

Brief description of what this PR is about

• If this change is a backward incompatible change, why must this change be made?
• Interesting edge cases to note here

[codecov-commenter]

Codecov Report

Patch coverage: 71.62% and project coverage change: +1.43 🎉

Comparison is base (bb5073f) 72.08% compared to head (6725238) 73.52%.

❗ Current head 6725238 differs from pull request most recent head 6d4453f. Consider uploading reports for the commit 6d4453f to get more accurate results

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Additional details and impacted files

@@             Coverage Diff              @@
##             master    #2578      +/-   ##
============================================
+ Coverage     72.08%   73.52%   +1.43%     
- Complexity     5126     6954    +1828     
============================================
  Files           473      684     +211     
  Lines         21970    30395    +8425     
  Branches       2351     3152     +801     
============================================
+ Hits          15838    22348    +6510     
- Misses         4925     6515    +1590     
- Partials       1207     1532     +325     

Impacted Files	Coverage Δ
api/src/main/java/ai/djl/modality/cv/Image.java	69.23% <ø> (-4.11%)	⬇️
...rc/main/java/ai/djl/modality/cv/MultiBoxPrior.java	76.00% <ø> (ø)
.../main/java/ai/djl/modality/cv/output/Landmark.java	100.00% <ø> (ø)
...i/djl/modality/cv/translator/BigGANTranslator.java	21.42% <0.00%> (-5.24%)	⬇️
.../modality/cv/translator/ImageFeatureExtractor.java	0.00% <0.00%> (ø)
.../ai/djl/modality/cv/translator/YoloTranslator.java	27.77% <0.00%> (+18.95%)	⬆️
...ain/java/ai/djl/modality/cv/util/NDImageUtils.java	67.10% <0.00%> (+7.89%)	⬆️
api/src/main/java/ai/djl/modality/nlp/Decoder.java	63.63% <ø> (ø)
api/src/main/java/ai/djl/modality/nlp/Encoder.java	66.66% <ø> (ø)
.../main/java/ai/djl/modality/nlp/EncoderDecoder.java	64.00% <ø> (ø)
... and 228 more

... and 352 files with indirect coverage changes

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