main/busybox: enable feature pidfile in busybox-extras

It's enabled in busyboxconfig and I don't see the point why not enable it for extras as well. At minimum, udhcpd is affected by this and it's openrc script is broken since it relies on the pidfile that's never generated.
7 jobs for !11030 with busybox-extras-enablePidFile in 3 minutes and 30 seconds
detached
Status Job ID Name Coverage
  Lint
failed #178847
x86_64 docker-alpine allowed to fail
lint

00:00:21

 
  Build
passed #178852
aarch64 ci-build docker-alpine
build-aarch64

00:01:25

passed #178853
armv7 ci-build docker-alpine
build-armv7

00:01:30

passed #178851
ppc64le ci-build docker-alpine
build-ppc64le

00:01:59

passed #178850
s390x ci-build docker-alpine
build-s390x

00:01:08

passed #178849
x86 ci-build docker-alpine
build-x86

00:01:03

passed #178848
x86_64 ci-build docker-alpine
build-x86_64

00:00:58

 
Name Stage Failure
failed
lint Lint
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