[Presentation] Make PresentationRequest.getAvailability() return a new Promise
According to the spec[1], PresentationRequest.getAvailability() should
return a new Promise when called each time.
[1] https://www.w3.org/TR/presentation-api/#dom-presentationrequest-getavailability
Bug: 41455951
Change-Id: I28611ea114d760d72cc395be48f7b028ee626a91
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5986368
Commit-Queue: Wei4 Wang wei4.wang@intel.com
Reviewed-by: Mark Foltz mfoltz@chromium.org
Cr-Commit-Position: refs/heads/main@{#1381009}