Removes install_dependencies from revdepcheck action (#289)

# Pull Request

Removes the unnecessary step that pre-installs packages from the
development branch.

Keeping this section would pre-install the `Remotes` section for the
CRAN checks, which may make it impossible to run when:

- development versions of dependencies no longer have API

### How to reproduce:

Current `teal` has this problem as development `teal.reporter` has
removed some internal API that was still being used in CRAN

#### 1 This run suffers from this case when setting up the CRAN version:
[link](https://github.com/insightsengineering/teal/actions/runs/18902061636/job/53951384382)

<img width="710" height="209" alt="image"
src="https://github.com/user-attachments/assets/b276df74-2935-4f8f-b0aa-7761564afbb7"
/>

#### 1.1 Same run conditions with extra debug that says that API is
missing:
[link](https://github.com/insightsengineering/teal/actions/runs/18901249737/job/53955439826)

<img width="869" height="572" alt="image"
src="https://github.com/user-attachments/assets/80420406-7186-43d6-9682-0b28ca090e3a"
/>

#### 2. Success with this PR:
[link](https://github.com/insightsengineering/teal/actions/runs/18904040693/job/53957871963)

<img width="733" height="189" alt="image"
src="https://github.com/user-attachments/assets/236e3288-32ff-4de3-91d3-1326159a1fa1"
/>

#### 3. Success in `teal.reporter`

Reverse case, nothing changes here


https://github.com/insightsengineering/teal.reporter/actions/runs/18904944232/job/53960828526

Author: averissimo

.github/workflows/revdepcheck.yaml

@@ -90,14 +90,6 @@ jobs:
           echo "gchat_webhook=${{ secrets.GCHAT_WEBHOOK }}" >> $GITHUB_ENV
         shell: bash
 
-      - name: Install dependencies
-        uses: insightsengineering/setup-r-dependencies@v1
-        env:
-          GITHUB_PAT: ${{ steps.github-token.outputs.token }}
-        with:
-          lookup-refs: ${{ inputs.lookup-refs }}
-          skip-desc-branch: true
-
       - name: revdepcheck 🔄
         id: revdepcheck
         uses: insightsengineering/r-revdepcheck-action@main