[Shipping labels] Disable "Select all" for fulfilled shipments

[RafaelKayumov]

Description

Makes the "Select all" navigation bar item disabled for a fulfilled shipment. More in discussion: p1745586909868109-slack-C03L1NF1EA3

Testing steps

• Log in to a test store with Woo Shipping plugin set up.
• Navigate to the Orders tab and select a completed order with at lest one shipment with a purchased label and at least one shipment without a label.
• Select the fulfilled shipment.
• Make sure the top left "Select all" option is disabled.
• Switch to unfulfilled shipment and make sure the "Select all" get enabled.
• Switch between shipments and make sure the "Select all" has corresponding valid enabled/disabled state.

Screenshots

Before	After

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• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

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[wpmobilebot]

📲 You can test the changes from this Pull Request in WooCommerce iOS Prototype by scanning the QR code below to install the corresponding build.

	App Name	WooCommerce iOS Prototype
	Build Number	29781
	Version	PR #15614
	Bundle ID	com.automattic.alpha.woocommerce
	Commit	799804d
	Installation URL	5pr8bif195q38

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[itsmeichigo]

Thanks for the fix - it works as described. I left a comment regarding the condition check.

[itsmeichigo]

Should we keep both conditions? If yes, combining them in a separate property enablesSelectAll in the view model would make it clearer.