Fix RccMainMenuBodyComponent bug in default theme

Building any variant with the default theme throws the following error:

Error: lib/themes/default/main-menu-body/main-menu-body.component.html:21:45 - error TS2551: Property 'metaAction' does not exist on type 'RccMainMenuBodyComponent'. Did you mean 'metaActions'?

It is indeed just a typo.