Add option to prevent "updates" on unmodified updates.

[kiwicopple]

Possible implementation:

const mySubscription = supabase
  .from('countries')
  .on('UPDATE', payload => {  })
  .subscribe({ ignoreDuplicates: true })

Object comparisons in JS aren't very "performant" (if there is such a word), so we will want to make the ignoreDuplicates = false by default.

Context:

[kiwicopple]

Note that we only need this in the supabase-js level, I don't think it needs to be in realtime-js