Revert "EventLogging role: set a local $wgEventLoggingSchemaApiUri"

This reverts commit c0ddfd28f28b4ccc7410a262c645635264a255cb.

Making the meta.wikimedia.org schemas unavailable for development is
not helpful; see the bug for details.

Bug: 70979
Change-Id: I1b0337f7c07bdfae4e79b0dd107d66e901c3facb