FEDX-518 Now that dart_dev itself is null-safe, it should be able to generate a null-safe run script

[evanweible-wf]

Problem

When we migrated this package to null-safe, we missed some logic in our run script generation that would include a Dart language comment to set the language version to 2.9 by default. This prevents the null-safe dart_dev from being able to run on Dart 3 where null-safety is required.

Solution

Remove this logic as it's no longer needed. We'll still copy over a language comment from tool/dart_dev/config.dart if one exists, otherwise we omit it which will allow dart_dev to run on Dart 3.

[aviary3-wk]

Security Insights

No security relevant content was detected by automated scans.

Action Items

• Review PR for security impact; comment "security review required" if needed or unsure
• Verify aviary.yaml coverage of security relevant code

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Questions or Comments? Reach out on Slack: #support-infosec.

[greglittlefield-wf]

• Changes look good
• Existing functional tests pass, that verify that dart_dev works as expected when packages have opted into null safety
• Manually tested in a package that is not yet opted into null safety and has a custom config, and dart_dev commands work as expected

+10

[evanweible-wf]

@Workiva/release-management-p

[rmconsole-wf]

+1 from RM