Update azure-key-vault.md - Fix azure portal link

[CrommVardek]

Fix azure portal link to https://portal.azure.com/

[prmerger-automator[bot]]

@CrommVardek : Thanks for your contribution! The author(s) have been notified to review your proposed change.

[Court72]

@ramiMSFT

Can you review the proposed changes?

When the changes are ready for publication, add a #sign-off comment to signal that the PR is ready for the review team to merge.

#label:"aq-pr-triaged" @MicrosoftDocs/public-repo-pr-review-team

[ramiMSFT]

@CrommVardek Thanks for your contribution! I fixed a merge conflict.

#sign-off