[CI] Remove sycl-devops-pr/** hack (#16754)

It was originally added in #10002,
back when we used `pull_request_target` for pre-commit trigger. Now that
`pull_request` is used it isn't (as) necessary.

I'm also adding a `workflow_dispatch` trigger for the post-commit job
for cases when somebody wants to test extensive non-CI changes with
post-commit before the merge. I think that will work but it's impossible
to verify before merging this due to how GHA work.

This will address the following usage scenario:
* Push CI-related changes to `sycl-devops-pr` (possibly several
iterations)
  * Result are ok, open a PR from that branch
- extra post-commit task is spawned for the commit that has been tested
already (this duplication will remain, unfortunately)
  * Address review feedback with a new upload
- two post-commit jobs are automatically launched (after this PR, no
manual dispatch would happen here, leaving only automatic pre-commit
testing of the post-commit workflow)

.github/workflows/pr-code-format.yml

@@ -8,7 +8,6 @@ on:
     branches:
       - main
       - sycl
-      - sycl-devops-pr/**
       - sycl-rel-**
       - 'users/**'
 

.github/workflows/sycl-linux-precommit.yml

@@ -7,7 +7,6 @@ on:
   pull_request:
     branches:
     - sycl
-    - sycl-devops-pr/**
     - sycl-rel-**
     # Do not run builds if changes are only in the following locations
     paths-ignore:

.github/workflows/sycl-post-commit.yml

@@ -1,16 +1,16 @@
 name: SYCL Post Commit
 
 on:
+  workflow_dispatch:
+
   push:
     branches:
     - sycl
-    - sycl-devops-pr/**
     - sycl-rel-**
 
   pull_request:
     branches:
     - sycl
-    - sycl-devops-pr/**
     paths:
     - .github/workflows/sycl-post-commit.yml
     - .github/workflows/sycl-linux-build.yml

.github/workflows/sycl-windows-precommit.yml

@@ -4,7 +4,6 @@ on:
   pull_request:
     branches:
     - sycl
-    - sycl-devops-pr/**
     - llvmspirv_pulldown
     - sycl-rel-**
     # Do not run builds if changes are only in the following locations