XWIKI-11411: UI extension parameters can redifined main VelocityContext bindings
XWIKI-11410: UI extensions parameters are executed in root Velocity namespace

(cherry picked from commit 4533b98fb45a9010198582a7053bc67e0b81b26d)

Conflicts:
	xwiki-platform-core/xwiki-platform-uiextension/xwiki-platform-uiextension-api/src/main/java/org/xwiki/uiextension/internal/WikiUIExtensionComponentBuilder.java