fix(ec2-metadata-service): custom port configuration for IMDS requests

[siddsriv]

Issue

#7285

Description

Ensure port value can be set and respected for IMDS requests.

Testing

New unit tests:

 ✓ MetadataService Custom Ports > should use custom port from endpoint URL in request() 1ms
   ✓ MetadataService Custom Ports > should use custom port from endpoint URL in fetchMetadataToken() 0ms
   ✓ MetadataService Custom Ports > should use undefined port for standard HTTP endpoint 0ms
   ✓ MetadataService Custom Ports > should use custom HTTPS port from endpoint URL 0ms

 Test Files  1 passed (1)
      Tests  16 passed (16)

---

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.