Added default-packages to setup-miniconda (#5789)

By default setup-miniconda installs a bunch of packages that may cause
conflicts with packages the user wants to install.

So add a parameter that can control the default packages. A user could
set it to empty if they don't want to install anything but python.

More context: I was using this library and getting failures when
installing ffmpeg7:


![image](https://github.com/user-attachments/assets/34514055-a518-41bf-965d-22e35190f988)



https://github.com/pytorch/torchcodec/actions/runs/11431285586/job/31800252965?pr=272

After this change I can install ffmpeg successfully by specifying it in
the default-packages list.

.github/actions/setup-miniconda/action.yml

@@ -24,6 +24,11 @@ inputs:
     required: false
     type: string
     default: ""
+  default-packages:
+    description: Default packages to install
+    required: false
+    type: string
+    default: "cmake=3.22 ninja=1.10 pkg-config=0.29 wheel=0.37"
 
 runs:
   using: composite
@@ -133,10 +138,7 @@ runs:
             --prefix "${CONDA_BASE_ENV}" \
             ${ENV_FILE_FLAG} \
             python="${PYTHON_VERSION}" \
-            cmake=3.22 \
-            ninja=1.10 \
-            pkg-config=0.29 \
-            wheel=0.37 \
+            ${{ inputs.default-packages }} \
             ${CONDA_EXTRA_FLAGS}
 
           if [[ -f "${PIP_REQUIREMENTS_FILE}" ]]; then