fix(positioning): use first placement as the fallback (#3017)
fix(positioning): use first placement as the fallback (#3017)

In case nothing matches from the positioning array, use the first value instead of the last one
fbasso/ng-bootstrap,fbasso/ng-bootstrap,benouat/ng-bootstrap,benouat/ng-bootstrap,ng-bootstrap/ng-bootstrap,jnizet/ng-bootstrap,fbasso/ng-bootstrap,ng-bootstrap/ng-bootstrap,maxokorokov/core,ng-bootstrap/ng-bootstrap,maxokorokov/core,fbasso/ng-bootstrap,jnizet/ng-bootstrap,maxokorokov/core,ng-bootstrap/ng-bootstrap,maxokorokov/core,jnizet/ng-bootstrap,benouat/ng-bootstrap,jnizet/ng-bootstrap,benouat/ng-bootstrap