[ubaskota]

Issue #, if available:

Description of changes:
Add web identity credential feature IDs

Add the User-Agent business metrics feature IDs for STS AssumeRoleWithWebIdentity credentials to AwsFeatureId:

• CREDENTIALS_ENV_VARS_STS_WEB_ID_TOKEN ("h"): web identity configured by environment variables
• CREDENTIALS_STS_ASSUME_ROLE_WEB_ID ("k"): credentials resolved with AssumeRoleWithWebIdentity
• CREDENTIALS_PROFILE_STS_WEB_ID_TOKEN ("q"): web identity configured by a shared config profile

These let the web identity credential providers in aws-credentials-sts record how credentials were resolved.

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

[jonathan343]

nit - This is more important for the future world when we're more stable: I think a change like this should be an enhancement instead of feature. feature changes trigger minor bumps. I understand why you want it here since it ensures the next client release will use a version that has these feature ids. However, feature id registration should be robust (meaning it shouldn't blow up when trying to register an unknown value). So I think this going out in a patch bump is the right move. I don't think triggering a minor bump for SDK clients should be a result of adding new feature ids.

Suggested change

	"type": "feature",
	"type": "enhancement",

[jonathan343]

Tests are failing:

make check-py
make[1]: Entering directory '/home/runner/work/smithy-python/smithy-python'
uv run ruff check packages --config pyproject.toml
S105 Possible hardcoded password assigned to: "CREDENTIALS_ENV_VARS_STS_WEB_ID_TOKEN"
  --> packages/smithy-aws-core/src/smithy_aws_core/business_metrics.py:56:45
   |
54 |     CREDENTIALS_CODE = "e"
55 |     CREDENTIALS_ENV_VARS = "g"
56 |     CREDENTIALS_ENV_VARS_STS_WEB_ID_TOKEN = "h"
   |                                             ^^^
57 |     CREDENTIALS_STS_ASSUME_ROLE_WEB_ID = "k"
58 |     CREDENTIALS_PROFILE = "n"
   |

S105 Possible hardcoded password assigned to: "CREDENTIALS_PROFILE_STS_WEB_ID_TOKEN"
  --> packages/smithy-aws-core/src/smithy_aws_core/business_metrics.py:59:44
   |
57 |     CREDENTIALS_STS_ASSUME_ROLE_WEB_ID = "k"
58 |     CREDENTIALS_PROFILE = "n"
59 |     CREDENTIALS_PROFILE_STS_WEB_ID_TOKEN = "q"
   |                                            ^^^
60 |     CREDENTIALS_PROFILE_PROCESS = "v"
61 |     CREDENTIALS_PROCESS = "w"

We either need to rename or add in-line ignores for these checks