Remove unused WPDATA preprocessor macro

[mokagio]

It was part of the scaffold to introduce WordPressData but is no longer necessary.

To verify removing it caused no issues, see green CI build and the text searches in the screenshot below:

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[wpmobilebot]

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

	App Name	Jetpack
	Configuration	Release-Alpha
	Build Number	27579
	Version	PR #24517
	Bundle ID	com.jetpack.alpha
	Commit	3b7f0f8
	Installation URL	0u108u5hdqbrg

Automatticians: You can use our internal self-serve MC tool to give yourself access to those builds if needed.

[wpmobilebot]

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

	App Name	WordPress
	Configuration	Release-Alpha
	Build Number	27579
	Version	PR #24517
	Bundle ID	org.wordpress.alpha
	Commit	3b7f0f8
	Installation URL	76g7f6stsrr3o

Automatticians: You can use our internal self-serve MC tool to give yourself access to those builds if needed.