Tests: Use spec-compliant RGB(A) values in safecss_filter_attr tests.

`rgb(255, 50%, 0)` mixes numbers and percentages within the legacy comma-separated syntax, which is invalid per CSS Color Level 4 — only the modern space-separated syntax permits mixing. Switch the case to `rgb(255 50% 0)`. Also bring `rgba(100, 200, 300, 0.8)` into the 0–255 range (`250`) so the fixtures reflect realistic, valid colors rather than relying on browser clamping.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>

Author: t-hamano

tests/phpunit/tests/kses.php

@@ -1362,8 +1362,8 @@ public function data_safecss_filter_attr() {
 				'expected' => 'color: rgb(100%, 0%, 50%)',
 			),
 			array(
-				'css'      => 'color: rgb(255, 50%, 0)',
-				'expected' => 'color: rgb(255, 50%, 0)',
+				'css'      => 'color: rgb(255 50% 0)',
+				'expected' => 'color: rgb(255 50% 0)',
 			),
 			// RGBA color.
 			array(
@@ -1386,8 +1386,8 @@ public function data_safecss_filter_attr() {
 			),
 			// RGBA border color.
 			array(
-				'css'      => 'border-color: rgba(100, 200, 300, 0.8)',
-				'expected' => 'border-color: rgba(100, 200, 300, 0.8)',
+				'css'      => 'border-color: rgba(100, 200, 250, 0.8)',
+				'expected' => 'border-color: rgba(100, 200, 250, 0.8)',
 			),
 			// RGB color in `border` shorthand.
 			array(