fix: simplifies run command and removes a copy paste mistake

Author: faouziH21

.github/workflows/test_t8code_advection.yml

@@ -80,8 +80,6 @@ jobs:
 #
 #
     # build config vars
-   - name: ninja install
-      run: cd build && ninja install $MAKEFLAGS
     - name: Set test level
       run: export TEST_LEVEL_FLAG="-DT8CODE_TEST_LEVEL=${{ inputs.TEST_LEVEL }}"
            && echo TEST_LEVEL_FLAG="$TEST_LEVEL_FLAG" >> $GITHUB_ENV
@@ -109,6 +107,7 @@ jobs:
       with:
         name: test-suite_${{ inputs.BUILD_TYPE }}_MPI_${{ inputs.MPI }}_api.log
         path: build/Testing/Temporary/LastTest.log
-    - name: run advection test 1D Mesh
-      run: cd build/example/advection && ./t8_advection -u 1 -e 1 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -v 1
 
+    - name: run advection test 1D Mesh
+          working-directory: build/example/advection
+          run: ./t8_advection -u 1 -e 1 -l 2 -r 1 -T 0.5 -C 0.5 -a 1 -v 1