fix: add exact check for language and kind, referring docs

[asharma991]

PR Fixes:

• Referred exact check for language and kind then only performing show/hide operation for subtitles.
• https://videojs.com/guides/text-tracks/#showing-tracks-programmatically. I could've used forEach but TextTrackList doesn't seem to have that method https://developer.mozilla.org/en-US/docs/Web/API/TextTrackList#instance_properties

Resolves #297

Checklist before requesting a review

• I have performed a self-review of my code
• I assure there is no similar/duplicate pull request regarding same issue