… Actions

### What is this PR for?
This PR fixes deprecation warnings in GitHub Actions workflows by replacing the deprecated `auto-activate-base` parameter with `auto-activate` in the `conda-incubator/setup-miniconda<at>v3` action.

The `auto-activate-base` parameter has been deprecated in favor of the more clearly named `auto-activate` parameter. This change removes deprecation warnings from GitHub Actions workflow logs while maintaining identical functionality.

### What type of PR is it?
Bug Fix

### Todos
* [x] - Replace `auto-activate-base` with `auto-activate` in frontend.yml
* [x] - Replace `auto-activate-base` with `auto-activate` in core.yml

### What is the Jira issue?
* https://issues.apache.org/jira/browse/ZEPPELIN-6403

### How should this be tested?
* Verify that GitHub Actions workflows run without deprecation warnings
* Confirm that all conda environment setup steps work correctly
* Check that Python and R interpreters are properly activated in CI jobs

Manual testing:
1. Push the changes to a branch
2. Observe GitHub Actions workflow runs
3. Confirm no deprecation warnings appear in the setup-miniconda steps
4. Verify all jobs complete successfully

### Screenshots (if appropriate)

**Before (with deprecation warning):**
<img width="1408" height="486" alt="image" src="https://github.com/user-attachments/assets/fba1149a-074f-4fe2-a8aa-645a822ae5b4" />

### Questions:
* Does the license files need to update? No.
* Is there breaking changes for older versions? No.
* Does this needs documentation? No.


Closes apache#5178 from ParkGyeongTae/ZEPPELIN-6403.

Signed-off-by: Jongyoul Lee <jongyoul@gmail.com>