activity#render passes all params to view context

do not limit params passed to view context via render. Currently it is impossible to pass i.e. ```formats: ['json']```.
See those tests for details: 
https://github.com/rails/rails/blob/b5e851e90bd1382fa1875d0a9fb2f997b817c25e/actionview/test/template/render_test.rb#L32

with this p/r P_A forwards everything as is unless explicitly modified.