fix(plugin-meetings): update transcription for new voicea payload

[mkesavan13]

COMPLETES SPARK-533905

This pull request addresses

As part of this PR: #3620 breaking changes were made to how captions are emitted in the events. This broke the Transcriptions in the plugin-meetings

by making the following changes

• Change everything to new payload structure
• Add timestamp in new payload for Voicea final captions
• Update voicea and SDK tests in plugin-meetings
• We also have refactored a util method,
  • Earlier, we were processing NEW_CAPTIONS in two data formats, isFinal:true came with "transcript" object while isFinal:false came with "transcripts" array
  • Now, the breaking change has aligned such that we always get only "transcripts" array
  • Therefore, this method now performs all the caption processing on "transcripts" array and only does the needed changes based on "isFinal" boolean. This means that we process isFinal:false as an interim caption while isFinal:true as final caption thereby removing the interim caption once we receive the final caption for the respective transcriptId
• Additionally, we also made changes to emitting spoken and caption languages as follows,
  • Earlier, the processing of spoken language and caption language wasn't accurate and this PR fixes it based on the SDK value of the caption language they had chosen earlier or set it from what the new caption event responds if not chosen via the SDK already

Change Type

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] Documentation update
• [ ] Tooling change
• [x] Internal code refactor

The following scenarios where tested

1. Ensured all the unit tests passed locally
2. Tested out from the Kitchen Sink app by enabling transcription and seeing if the live captions are generated without any errors
3. Set the Spoken Language to Hindi and spoke in Hindi. This translated the Caption from whatever I spoke in Hindi to English
4. Similarly set the Spoken Language back to English and the Caption language to Hindi. This translated the caption to Hindi from whatever I spoke in English. Verified the translation with Google Translate also

I certified that

• [x] I have read and followed contributing guidelines

• [x] I discussed changes with code owners prior to submitting this pull request

• [x] I have not skipped any automated checks

• [x] All existing and new tests passed

• [x] I have updated the documentation accordingly

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