fix(filtering): increase the min width of the filtering input and remove extra lines

Author: MPopov

projects/igniteui-angular/src/lib/core/styles/components/grid/_grid-theme.scss

@@ -2366,7 +2366,7 @@
         igx-input-group {
             width: 100%;
             max-width: rem(200px);
-            min-width: rem(100px);
+            min-width: rem(140px);
         }
 
         igx-prefix:focus {
@@ -2658,5 +2658,3 @@
         }
     }
 }
-
-