ci: Remove remaining nextest compiles (#42630)

Follow up to https://github.com/zed-industries/zed/pull/42556

Release Notes:

- N/A *or* Added/Fixed/Improved ...

.github/actions/run_tests/action.yml

@@ -4,10 +4,8 @@ description: "Runs the tests"
 runs:
   using: "composite"
   steps:
-    - name: Install Rust
-      shell: bash -euxo pipefail {0}
-      run: |
-        cargo install cargo-nextest --locked
+    - name: Install nextest
+      uses: taiki-e/install-action@nextest
 
     - name: Install Node
       uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4

.github/actions/run_tests_windows/action.yml

@@ -11,9 +11,8 @@ runs:
   using: "composite"
   steps:
     - name: Install test runner
-      shell: powershell
       working-directory: ${{ inputs.working-directory }}
-      run: cargo install cargo-nextest --locked
+      uses: taiki-e/install-action@nextest
 
     - name: Install Node
       uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4