pgsql: Avoid including worker_internal.h in pgstat.h.

Avoid including worker_internal.h in pgstat.h.

pgstat.h is a widely included header. Including worker_internal.h there is
unnecessary and creates tight coupling. By refactoring
pgstat_report_subscription_error() to fetch the required
LogicalRepWorkerType internally rather than receiving it as an argument,
we can eliminate the need for the internal header.

Reported-by: Andres Freund <andres(at)anarazel(dot)de>
Author: Nisha Moond <nisha(dot)moond412(at)gmail(dot)com>
Reviewed-by: vignesh C <vignesh21(at)gmail(dot)com>
Reviewed-by: Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
Discussion: https://postgr.es/m/aY-UE-4t7FiYgH3t@alap3.anarazel.de

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/9842e8aca096d9b988a3ae924cdf4aa7e1bb2ea2

Modified Files
--------------
src/backend/commands/functioncmds.c | 1 +
src/backend/replication/logical/sequencesync.c | 3 +--
src/backend/replication/logical/tablesync.c | 3 +--
src/backend/replication/logical/worker.c | 6 ++----
src/backend/storage/ipc/procsignal.c | 1 +
src/backend/utils/activity/pgstat_subscription.c | 3 ++-
src/include/pgstat.h | 4 +---
src/include/replication/worker_internal.h | 7 +++++++
src/test/modules/test_custom_stats/test_custom_var_stats.c | 1 +
9 files changed, 17 insertions(+), 12 deletions(-)