webnn: fix gather indices types
Gather should support indices types int32, uint32, int64.
Bug: 338640913
Change-Id: Id26827e8a199b2ca1574ec92aead8466f89a3cb0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5538980
Reviewed-by: Austin Sullivan asully@chromium.org
Commit-Queue: Phillis Tang phillis@chromium.org
Cr-Commit-Position: refs/heads/main@{#1301684}