Add wp_print_inline_script_tag within the WP Proxy class to facilitate testing the inline scripts

[jorgemd24]

Describe the bug:

This a follow-up of #2184

Currently, it is not possible to mock wp_print_inline_script_tag making it challenging to test various scenarios, like the scripts inserted for the gtag events. See this case:

google-listings-and-ads/src/Google/GlobalSiteTag.php

Lines 285 to 297 in d65b577

	$conversion_gtag_info =
	sprintf(
	'gtag("event", "conversion", {
	send_to: "%s",
	value: %f,
	currency: "%s",
	transaction_id: "%s"});',
	esc_js( "{$ads_conversion_id}/{$ads_conversion_label}" ),
	$order->get_total(),
	esc_js( $order->get_currency() ),
	esc_js( $order->get_id() ),
	);
	wp_print_inline_script_tag( $conversion_gtag_info );

If we add wp_print_inline_script_tag within the WP Proxy class we will be able to mock the method and therefore to test different scenarios easily, similar what is done here:

google-listings-and-ads/tests/Unit/API/Google/AdsAssetTest.php

Lines 132 to 143 in d65b577

	$this->wp->expects( $this->exactly( 1 ) )
	->method( 'wp_remote_get' )
	->with( $data['content'] )
	->willReturn(
	[
	'body' => $data['content'],
	'headers' => new ArrayObject( [ 'content-length' => 12345 ] ),
	]
	);
	$this->generate_asset_mutate_mock( 'create', $data );
	$this->assertEquals( $this->generate_asset_resource_name( $data['id'] ), $this->asset->create_assets( [ $data ] )[0] );

Expected behavior:

To be able to mock wp_print_inline_script_tag easily

Actual behavior:

Difficult to mock wp_print_inline_script_tag

Additional details: