Add enhanced Azure Student Plan workaround steps

[0xgeorgeassaad]

Adds a dedicated Azure Student Plan Workaround section under VM Size / Capacity Errors, covering:

• Checking allowed deployment regions via Azure Portal -> Policy -> Assignments-> Allowed resource deployment regions
• Verifying Standard_B2ts_v2 availability with az vm list-skus before switching from the default Standard_B1s

The top-level student account note now links to this section first, with the existing external guide kept as a fallback.

[madebygps]

Thanks for adding this! The Azure Policy steps are genuinely useful and fill a gap in our current troubleshooting guidance.

To keep the documentation evergreen, could we focus this section on discovering the subscription’s allowed regions, then link back to the generic SKU checks in TROUBLESHOOTING.md?

The B1s/B2ts_v2 and Spain Central example feels account-specific and may age quickly. This would preserve the unique value while teaching learners how to find a working region/SKU themselves.