Fix args overwrite bug in exlude_tags

[klemens-st]

Right now instead of $args, $params are passed to lcp_excluded_tags. This small bug means that if a user specifies exclude_tags shortcode parameter, two things happen:

1. Any $args set and parsed above line 142 of lcp-parameters.php will be ignored, e.g. excludeposts, before_year etc.
2. A full array of raw LCP parameters will be passed to WP_Query

This is fixed in this PR.

Fixes https://wordpress.org/support/topic/excludepoststhis-not-working/

[picandocodigo]

Thanks as always @zymeth25! I haven't had much time recently, but as soon as I do, I'll try to get the rest of the PR's in.

[klemens-st]

@picandocodigo Great! No rush about the rest, I'll keep sending small fixes when necessary but to continue refactoring and making things easier we need to deal with #288 first.