Roll src/third_party/libvpx/source/libvpx/ b32e98f52..6bb288633 (2 commits)

https://chromium.googlesource.com/webm/libvpx.git/+log/b32e98f52fb9..6bb288633613

$ git log b32e98f52..6bb288633 --date=short --no-merges --format='%ad %ae %s'
2025-05-01 wtc Replace memcpy() calls with struct assignments
2025-04-30 jzern vpx_codec_enc_init_multi: fix double free on init failure

Created with:
  roll-dep src/third_party/libvpx/source/libvpx
R=vigneshv@google.com

Bug: b:308446709, webm:413411335
Change-Id: Ib9ddfddbcab6924bdb886a0a34f21386888003f2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6506844
Reviewed-by: Vignesh Venkat <vigneshv@google.com>
Commit-Queue: Vignesh Venkat <vigneshv@google.com>
Auto-Submit: Wan-Teh Chang <wtc@google.com>
Cr-Commit-Position: refs/heads/main@{#1455243}