Add unit tests for Plan.IsWarm() method

[coderabbitai]

Description

Add comprehensive unit tests for the Plan.IsWarm() method introduced in PR #3007.

Context

The IsWarm() method centralizes warm migration detection logic that was previously inline across multiple files. It checks both the legacy Spec.Warm flag and the new Spec.Type == MigrationWarm field.

Testing Requirements

Unit tests should cover:

• Spec.Warm = true returns true
• Spec.Type = MigrationWarm returns true
• Both fields set returns true
• Neither field set returns false
• Other migration types return false

References

• PR: MTV-3495 | type warm migration doesn't work properly #3007
• Discussion: MTV-3495 | type warm migration doesn't work properly #3007 (comment)
• Requested by: @yaacov

Location

pkg/apis/forklift/v1beta1/plan.go (lines 284-286)