make STS support for 'mc' alias specific

[harshavardhana]

Community Contribution License

All community contributions in this pull request are licensed to the project maintainers under the terms of the [Apache 2 license] (https://www.apache.org/licenses/LICENSE-2.0). By creating this pull request I represent that I have the right to license the contributions to the project maintainers under the Apache 2 license.

Description

make STS support for 'mc' alias specific

Motivation and Context

currently, STS-specific behavior is global, mc, however, supports multiple aliases - we need to make sure that mc treats this ENV specific to an alias.

How to test this PR?

Enhances support introduced in #4754 #4744

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Optimization (provides speedup with no functional changes)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [ ] Fixes a regression (If yes, please add commit-id or PR # here)
• [ ] Unit tests added/updated
• [ ] Internal documentation updated
• [ ] Create a documentation update request here

[pjuarezd]

catching up with this, looks good!