Update autosummary for Sphinx 8.2.1

[jsiirola]

Fixes # .

Summary/Motivation:

This resolves RTD failures induced by Sphinx changing their API in 8.2.1.

Changes proposed in this PR:

• Update Pyomo's generate_autosummart_content wrapper to track Sphinx API change
• Update ExtendedEnumMeta to include enum members from base enum in the results from dir(). This will ensure base enum members are documented by Sphinx

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