[Feature]: Support non-default runtimes for Automations

### Description of the new feature

Currently, the only way to upload PowerShell Modules or Python Packages to a non-default runtime is to use the portal. This process can be tedious and error-prone. This problem is exacerbated by the fact that the default runtimes are old, end-of-life versions of PowerShell and Python.

### Proposed implementation details (optional)

Accept a Runtime parameter to `New-AzAutomationModule` and `New-AzAutomationPython3Package`.

Start by locating the implementations and tests for New-AzAutomationModule and New-AzAutomationPython3Package. Trace how their upload parameters are passed to Azure Automation, then add coverage for a non-default Runtime value. Done means both cmdlets accept and use Runtime while preserving default behavior.

Written by the indexing model from the issue text.