lib: disable logging in dav1d_parse_sequence_header()

The function uses a Dav1dContext internally, so the caller can't disable
logging or use a custom logger. Play it safe and disable logging altogether
to avoid spamming stderr.
16 jobs for master in 5 minutes and 42 seconds (queued for 1 second)
Status Job ID Name Coverage
  Style
passed #249312
amd64 debian
style-check

00:00:21

 
  Build
passed #249313
amd64 debian
build-debian

00:00:33

passed #249320
debian aarch64
build-debian-aarch64

00:01:19

passed #249321
debian aarch64
build-debian-aarch64-clang-5

00:01:01

passed #249314
amd64 debian
build-debian-static

00:00:36

passed #249323
debian aarch64
build-debian-werror

00:00:32

passed #249315
amd64 debian
build-debian32

00:00:26

passed #249322
macos
build-macos

00:00:28

passed #249318
win32
build-win-arm32

00:00:27

passed #249319
win64
build-win-arm64

00:00:27

passed #249316
win32
build-win32

00:00:32

passed #249317
win64
build-win64

00:00:35

 
  Test
passed #249324
amd64 debian
test-debian

00:00:46

passed #249325
amd64 debian
test-debian-asan

00:02:05

passed #249326
amd64 debian
test-debian-msan

00:01:03

passed #249327
amd64 debian
test-debian-ubsan

00:01:20