composebox_typeahead: Remove unnecessary autocomplete_checks.
composebox_typeahead: Remove unnecessary autocomplete_checks.

The validations that autocomplete_checks did were already managed by
tokenize_compose_str and the main "if" statements in
compose_content_begins_typeahead.

jackrzhang/zulip,eeshangarg/zulip,kou/zulip,vabs22/zulip,tommyip/zulip,amanharitsh123/zulip,punchagan/zulip,eeshangarg/zulip,andersk/zulip,showell/zulip,tommyip/zulip,Galexrt/zulip,hackerkid/zulip,showell/zulip,tommyip/zulip,jrowan/zulip,kou/zulip,amanharitsh123/zulip,shubhamdhama/zulip,rishig/zulip,rishig/zulip,hackerkid/zulip,brockwhittaker/zulip,verma-varsha/zulip,kou/zulip,vabs22/zulip,dhcrzf/zulip,jackrzhang/zulip,dhcrzf/zulip,showell/zulip,brockwhittaker/zulip,shubhamdhama/zulip,synicalsyntax/zulip,mahim97/zulip,brockwhittaker/zulip,timabbott/zulip,timabbott/zulip,andersk/zulip,rht/zulip,vaidap/zulip,Galexrt/zulip,rht/zulip,amanharitsh123/zulip,andersk/zulip,vaidap/zulip,mahim97/zulip,rishig/zulip,tommyip/zulip,Galexrt/zulip,synicalsyntax/zulip,brainwane/zulip,synicalsyntax/zulip,timabbott/zulip,dhcrzf/zulip,amanharitsh123/zulip,hackerkid/zulip,hackerkid/zulip,rishig/zulip,verma-varsha/zulip,andersk/zulip,rht/zulip,punchagan/zulip,punchagan/zulip,jackrzhang/zulip,amanharitsh123/zulip,brainwane/zulip,kou/zulip,vaidap/zulip,hackerkid/zulip,synicalsyntax/zulip,vabs22/zulip,rishig/zulip,zulip/zulip,andersk/zulip,eeshangarg/zulip,shubhamdhama/zulip,shubhamdhama/zulip,dhcrzf/zulip,Galexrt/zulip,verma-varsha/zulip,vaidap/zulip,dhcrzf/zulip,punchagan/zulip,timabbott/zulip,brockwhittaker/zulip,shubhamdhama/zulip,rht/zulip,kou/zulip,jrowan/zulip,brainwane/zulip,punchagan/zulip,shubhamdhama/zulip,verma-varsha/zulip,Galexrt/zulip,timabbott/zulip,jackrzhang/zulip,andersk/zulip,vabs22/zulip,andersk/zulip,jrowan/zulip,synicalsyntax/zulip,jrowan/zulip,mahim97/zulip,synicalsyntax/zulip,verma-varsha/zulip,kou/zulip,eeshangarg/zulip,rht/zulip,eeshangarg/zulip,timabbott/zulip,rishig/zulip,vabs22/zulip,eeshangarg/zulip,zulip/zulip,zulip/zulip,vabs22/zulip,brockwhittaker/zulip,tommyip/zulip,mahim97/zulip,jackrzhang/zulip,vaidap/zulip,rishig/zulip,Galexrt/zulip,synicalsyntax/zulip,hackerkid/zulip,dhcrzf/zulip,shubhamdhama/zulip,zulip/zulip,showell/zulip,jrowan/zulip,rht/zulip,showell/zulip,jrowan/zulip,showell/zulip,brainwane/zulip,tommyip/zulip,dhcrzf/zulip,brainwane/zulip,hackerkid/zulip,brainwane/zulip,timabbott/zulip,mahim97/zulip,jackrzhang/zulip,zulip/zulip,amanharitsh123/zulip,punchagan/zulip,zulip/zulip,eeshangarg/zulip,punchagan/zulip,tommyip/zulip,jackrzhang/zulip,verma-varsha/zulip,kou/zulip,brockwhittaker/zulip,vaidap/zulip,zulip/zulip,mahim97/zulip,Galexrt/zulip,rht/zulip,brainwane/zulip,showell/zulip