Fix transcription for longer audio

[msluszniak]

Description

This PR introduces changes that fix transcription for audio longer than 30 seconds. It also fixes Speech to Text demo app. Previously, local paths to audio files hasn't worked. Now they worked.

Introduces a breaking change?

• Yes
• No

Type of change

• Bug fix (change which fixes an issue)
• New feature (change which adds functionality)
• Documentation update (improves or adds clarity to existing documentation)
• Other (chores, tests, code style improvements etc.)

Tested on

• iOS
• Android

Testing instructions

Before applying changes:
Run Speech to text demo app with audio longer than 30 seconds. Then, check that it has incorrect transcription
Additionally, try to pass path to local audio file and check, that transcription never starts.

Then, apply changes and check if these two issues are resolved

Screenshots

Related issues

Closes #740

Checklist

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have updated the documentation accordingly
• My changes generate no new warnings

Additional notes