.form-field .block-picker li:last-child{
	display:none !important;
}
.form-field .block-picker li:first-child{
	display: list-item !important;
}

/*Can be used the following instead of the above if required*/
/*.form-field .block-picker li:first-child, .form-field .block-picker li:last-child{
	display: list-item !important;
}
.form-field .block-picker li:last-child[data-block="1000"] { /*here 1000 can be replaced with the actual value of the last child item*/
  /*display: none !important;
}*/