[POS Orders] Remove feature flag

[toupper]

Description

With this PR we remove the feature flag so the POS Historical Orders functionality can be enabled in production.

Test Steps

CI should pass.

• I have considered if this change warrants release notes and have added them to RELEASE-NOTES.txt if necessary. Use the "[Internal]" label for non-user-facing changes.

[dangermattic]

	1 Warning
⚠️	This PR is assigned to the milestone 23.6. This milestone is due in less than 2 days. Please make sure to get it merged by then or assign it to a milestone with a later deadline.

Generated by 🚫 Danger

[wpmobilebot]

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

	App Name	WooCommerce-Wear Android
	Platform	⌚️ Wear OS
	Flavor	Jalapeno
	Build Type	Debug
	Commit	4464faa
	Direct Download	woocommerce-wear-prototype-build-pr14866-4464faa.apk

[wpmobilebot]

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

	App Name	WooCommerce Android
	Platform	📱 Mobile
	Flavor	Jalapeno
	Build Type	Debug
	Commit	4464faa
	Direct Download	woocommerce-prototype-build-pr14866-4464faa.apk

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 38.27%. Comparing base (7e5bb1b) to head (4464faa).

Additional details and impacted files

@@            Coverage Diff            @@
##              trunk   #14866   +/-   ##
=========================================
  Coverage     38.26%   38.27%           
- Complexity    10077    10078    +1     
=========================================
  Files          2131     2130    -1     
  Lines        120744   120738    -6     
  Branches      16547    16546    -1     
=========================================
+ Hits          46206    46208    +2     
+ Misses        69840    69834    -6     
+ Partials       4698     4696    -2     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[kidinov]

LGTM!