Soften diagnostic message for missing --environment flag

[Copilot]

Problem

When running azd with the --debug flag, users would see a diagnostic message that appeared error-like:

'azd foo'command asked for envFlag, but envFlag was not included in cmd.Flags().

This message looked like an error even though it represents normal, safe behavior (falling back to the default environment).

Changes

Updated the diagnostic message in cli/azd/cmd/container.go (line 184) to be more informational and user-friendly:

Before:

log.Printf("'%s'command asked for envFlag, but envFlag was not included in cmd.Flags().", cmd.CommandPath())

After:

log.Printf("'%s' command did not include --environment so using default environment instead.", cmd.CommandPath())

The new message:

• Adds the missing space after the command name
• Uses clearer, more informative language
• Explicitly indicates the fallback behavior (using default environment)
• Makes it clear this is expected and safe to ignore

Testing

• ✅ Code builds successfully
• ✅ All unit tests pass
• ✅ Code formatting and linting checks pass
• ✅ No spelling errors

Fixes #4444 (if there's an associated issue number)

Original prompt

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This section details on the original issue you should resolve

<issue_title>[Issue] Soften diagnostic message for missing --environment flag</issue_title>
<issue_description>Running azd with --debug will often show a trace like container.go:184: 'azd foo'command asked for envFlag, but envFlag was not included in cmd.Flags(). which looks like an error. We should change that message at https://github.com/Azure/azure-dev/blob/main/cli/azd/cmd/container.go#L184 to 'azd foo' command did not include --environment so using default environment instead so people know it's safe to ignore. Also make sure there's a space after the command name like the example there.</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes #5929

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[vhvb1989]

/check-enforcer override