Revert "install test dependencies with canary conda-libmamba-solver"

This reverts commit 0f556ca.

Author: danyeaw

.github/workflows/tests.yml

@@ -141,10 +141,6 @@ jobs:
           condarc-file: conda\.github\condarc-${{ matrix.default-channel }}
           run-post: false  # skip post cleanup
 
-      - name: Upgrade conda-libmamba-solver (without sharded repodata)
-        shell: bash
-        run: "CONDA_PLUGINS_USE_SHARDED_REPODATA=0 conda install --yes -n base conda-canary/label/dev::conda-libmamba-solver"
-
       - name: Conda Install
         working-directory: conda  # CONDA-LIBMAMBA-SOLVER CHANGE
         # CONDA-LIBMAMBA-SOLVER CHANGE: add conda-libmamba-solver requirements.txt
@@ -310,9 +306,6 @@ jobs:
           condarc-file: conda/.github/condarc-${{ matrix.default-channel }}
           run-post: false  # skip post cleanup
 
-      - name: Upgrade conda-libmamba-solver (without sharded repodata)
-        run: CONDA_PLUGINS_USE_SHARDED_REPODATA=0 conda install --yes -n base conda-canary/label/dev::conda-libmamba-solver
-
       - name: Conda Install
         working-directory: conda
         run: >
@@ -589,9 +582,6 @@ jobs:
           miniforge-version: ${{ (matrix.default-channel == 'conda-forge' && matrix.arch == 'osx-64') && 'latest' || null }}
           architecture: ${{ runner.arch }}
 
-      - name: Upgrade conda-libmamba-solver (without sharded repodata)
-        run: CONDA_PLUGINS_USE_SHARDED_REPODATA=0 conda install --yes -n base conda-canary/label/dev::conda-libmamba-solver
-
       - name: Conda Install
         working-directory: conda # CONDA-LIBMAMBA-SOLVER CHANGE
         # CONDA-LIBMAMBA-SOLVER CHANGE: add conda-libmamba-solver requirements.txt