gh-35845: Allow sphinx <= 7.x and other conda related improvements

    
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### 📚 Description

Allow sphinx 6 and 7 to be installed (using conda) since after
#35658 this no longer leeds to
errors.
Also disable the `enviroment-optional` matrix testing since this is
currently broken  (can easily be renenabled in the PR that fixes it),
and always run the test step in the conda workflow.


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### ⌛ Dependencies

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URL: #35845
Reported by: Tobias Diez
Reviewer(s): François Bissey, Matthias Köppe, Tobias Diez

.github/workflows/ci-conda.yml

@@ -34,7 +34,9 @@ jobs:
       matrix:
         os: [ubuntu-latest, macos-latest]
         python: ['3.9', '3.10', '3.11']
-        conda-env: [environment, environment-optional]
+        # Optional environment is disabled for now as its not yet working
+        # environment: [environment, environment-optional]
+        conda-env: [environment]
 
     steps:
       - uses: actions/checkout@v3
@@ -100,19 +102,20 @@ jobs:
           SAGE_NUM_THREADS: 2
 
       - name: Verify dependencies
-        if: always()
+        if: success() || failure()
         shell: bash -l {0}
         run: pip check
 
       - name: Test
+        if: success() || failure()
         shell: bash -l {0}
         run: ./sage -t --all -p0
 
       - name: Print logs
+        if: always()
         run: |
           for file in $(find . -type f -name "*.log"); do
               echo "::group::$file"
               cat "$file"
               echo "::endgroup::"
           done
-        if: always()

build/pkgs/sphinx/distros/conda.txt

@@ -1 +1 @@
-sphinx<6,>=5.2
+sphinx<8,>=5.2

build/pkgs/sphinx/install-requires.txt

@@ -1 +1 @@
-sphinx >=5.2, <6
+sphinx >=5.2, <8