Run FreeBSD jobs automatically for all pipelines

No problems have been observed on the FreeBSD GitLab CI runner during
the burn-in period, when FreeBSD jobs needed to be triggered manually.
Thus, make the FreeBSD jobs run automatically along other GitLab CI
jobs.

.gitlab-ci.yml

@@ -676,7 +676,6 @@ clang:freebsd11.3:amd64:
     CFLAGS: "-Wall -Wextra -O2 -g"
   <<: *freebsd_amd64
   <<: *build_job
-  when: manual
 
 system:clang:freebsd11.3:amd64:
   <<: *freebsd_amd64
@@ -684,7 +683,6 @@ system:clang:freebsd11.3:amd64:
   dependencies:
     - clang:freebsd11.3:amd64
   needs: ["clang:freebsd11.3:amd64"]
-  when: manual
 
 unit:clang:freebsd11.3:amd64:
   <<: *freebsd_amd64
@@ -692,7 +690,6 @@ unit:clang:freebsd11.3:amd64:
   dependencies:
     - clang:freebsd11.3:amd64
   needs: ["clang:freebsd11.3:amd64"]
-  when: manual
 
 # Jobs for Clang builds on FreeBSD 12.0 (amd64)
 
@@ -702,7 +699,6 @@ clang:freebsd12.0:amd64:
     EXTRA_CONFIGURE: "--enable-dnstap"
   <<: *freebsd_amd64
   <<: *build_job
-  when: manual
 
 system:clang:freebsd12.0:amd64:
   <<: *freebsd_amd64
@@ -710,7 +706,6 @@ system:clang:freebsd12.0:amd64:
   dependencies:
     - clang:freebsd12.0:amd64
   needs: ["clang:freebsd12.0:amd64"]
-  when: manual
 
 unit:clang:freebsd12.0:amd64:
   <<: *freebsd_amd64
@@ -718,7 +713,6 @@ unit:clang:freebsd12.0:amd64:
   dependencies:
     - clang:freebsd12.0:amd64
   needs: ["clang:freebsd12.0:amd64"]
-  when: manual
 
 # Jobs with libtool disabled