Update filename numbering to match quickstarts/ on dapr-agents

[seherv]

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Description

Changes the command snippets in the Dapr Agents quickstarts to match the actual numbering of the files in the repo.
Also adds the missing link to the second quickstart (used 02_durable_agent_workflow.py) to the Fundamentals table.

Issue reference

Closes dapr-agents #573.

[CasperGN]

LGTM