media: Fix typo in feature name kUseSequencedTaskRunnerForVEA

The feature name was misspelled as `kUSeSequencedTaskRunnerForVEA`. This
commit corrects the capitalization to `kUseSequencedTaskRunnerForVEA` in
its definition, declaration, and usage.

With this change, we can also use the new 2-param BASE_FEATURE macro.

Bug: 436274260
Change-Id: I0d8fc0d5a64c9272afe16d6a88770cac97e9385e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6952851
Auto-Submit: Xiaohan Wang <xhwang@chromium.org>
Commit-Queue: Phil Yan <philyan@chromium.org>
Reviewed-by: Phil Yan <philyan@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1515867}