docs: Update Readmefile as per Post deployment script chnages

[NirajC-Microsoft]

Purpose

This pull request updates the instructions for importing sample data in the deployment guide to simplify the process and clarify what to do if the deployment does not exist. The main change is that the sample data import script now only requires the resourceGroupName parameter, and the script will prompt for additional values if needed.

Documentation improvements:

• Updated the sample data import instructions in docs/DeploymentGuide.md to require only resourceGroupName as a parameter for the process_sample_data.sh script, and clarified that the script will prompt for additional values if the deployment does not exist.
• ...

Does this introduce a breaking change?

• Yes
• No

Golden Path Validation

• I have tested the primary workflows (the "golden path") to ensure they function correctly without errors.

Deployment Validation

• I have validated the deployment process successfully and all services are running as expected with this change.

What to Check

Verify that the following are valid

• ...

Other Information