Change readme instructions to initialize user secrets from command line

[asanjabi]

Describe the bug Current instructions ask user to open the .sln file to initialize user secrets. Doing this from command line using dotnet user-secrets init would work for more environments. It can be added to the getSecretsForLocalDev script also, or omitted if the UserSecret tag is already set in the project files.

To Reproduce Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior A clear and concise description of what you expected to happen.

Screenshots If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: [e.g. Windows, macOS]
• Shell [e.g. PowerShell Core, Bash]
• Shell Version [e.g. PowerShell 7.3.3]
• az version [e.g.]

        "azure-cli": "2.46.0",
        "azure-cli-core": "2.46.0",
        "azure-cli-telemetry": "1.0.8",
        "extensions": 
             "aks-preview": "0.5.100",
             "containerapp": "0.3.10",
             "deploy-to-azure": "0.2.0"

• az bicep version [e.g., Bicep CLI version 0.15.31 (3ba6e06a8d)]
• azd version [e.g., azd version 0.7.0-beta.1 (commit 9ce71659f7688d0dc3dda8b84e5accedca58cf01)]
• dotnet --version [e.g., 6.0.407]

Additional context Add any other context about the problem here.

[KSchlobohm]

migrated to 1852564