Clean up SSL_CTX_set_grease_sigalgs_enabled call

As of BORINGSSL_API_VERSION 44, the functionality has been folded into
SSL_CTX_set_grease_enabled, which is already called. Now that BoringSSL
has been updated to version 44, delete the old code.

Bug: 526597789
Change-Id: Ib79f48540ef25c7ffe4f0e75650035be6a6a6964
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/8571900
Reviewed-by: David Benjamin <davidben@chromium.org>
Commit-Queue: David Benjamin <davidben@chromium.org>
Auto-Submit: Lily Chen <chlily@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1720697}
NOKEYCHECK=True
GitOrigin-RevId: 07e18b4809adfabecccde8bef4fc031370811fe0