ACK runtime `pkg/compare/Delta.DifferentAt` is not working with fields JSON-Paths

[a-hilaly]

Describe the bug
delta.DifferentAt doesn't work as expected when getting fields JSON-Path as input - see differentAt unit tests

delta.Add("Spec.X.Y.Z", a, b)
delta.DifferentAt("Spec.X.Y") // returns false
delta.DifferentAt("Y")        // returns true

Expected outcome

delta.Add("Spec.X.Y.Z", a, b)
delta.DifferentAt("Spec.X.Y") // should return true
delta.DifferentAt("Y")        // should return false

/priority important-soon
/good-first-issue
/help-wanted

[ack-bot]

@a-hilaly:
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In response to this:

Describe the bug
delta.DifferentAt doesn't work as expected when getting fields JSON-Path as input - see differentAt unit tests

delta.Add("Spec.X.Y.Z", a, b)
delta.DifferentAt("Spec.X.Y") // returns false
delta.DifferentAt("Y")        // returns true

Expected outcome

delta.Add("Spec.X.Y.Z", a, b)
delta.DifferentAt("Spec.X.Y") // should return true
delta.DifferentAt("Y")        // should return false

/priority important-soon
/good-first-issue
/help-wanted

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