Link metrics example filenames to docs/examples files

[saisharan0103]

The metrics example README pages listed individual Python files as plain text, so rendered Read the Docs pages did not give users direct GitHub links to the referenced code despite existing :scm_web: support.

This updates the file bullet lists in docs/examples/metrics/reader/README.rst and docs/examples/metrics/views/README.rst so each referenced Python filename uses a :scm_web: role pointing at the actual file under docs/examples. The existing directory-level :scm_web: links are left in place.

The metrics views list also now includes the existing disable_default_aggregation.py example with a short description consistent with the nearby entries.

Fixes #5427.

ruff check docs/examples/metrics/reader/README.rst docs/examples/metrics/views/README.rst reports no new findings on the changed files.
Ran pytest -x locally with no new failures.

[linux-foundation-easycla]

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