…ws-observability#549)

*Issue #, if available:*

When using the OpenTelemetry Django instrumentation, users must set the
DJANGO_SETTINGS_MODULE environment variable before Python starts.
Otherwise, Django will fail to launch because it cannot locate the
required settings module.

*Description of changes:*
In the ADOT distribution, we can add logic so that if Django is
installed, the Django instrumentation is enabled only when the
DJANGO_SETTINGS_MODULE environment variable is present.

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

*Issue #, if available:*
N/A - Patch release preparation

**Description of changes:**

Cherry-pick commits from main to prepare v0.14.1 patch release:
  - #554 - Add custom ADOT UserAgent for OTLP Spans Exporter
- #552 - Refactor configuration for Application Signals Dimensions to
EMF exporter
  - #551 - CVE-2025-66471 fix (urllib3 dependency bump)
- #549 - Disable django instrumentation if DJANGO_SETTINGS_MODULE is not
set
  - #548 - Add Service and Environment dimensions to EMF metrics
  - #547 - Add safety check for bedrock ConverseStream responses
  - #546 - Fix python package distribution name case-sensitive issue

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

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Co-authored-by: Lei Wang <66336933+wangzlei@users.noreply.github.com>
Co-authored-by: Steve Liu <liustve@amazon.com>
Co-authored-by: Syed Ahsan Ishtiaque <176968742+syed-ahsan-ishtiaque@users.noreply.github.com>