removeBlankRows

function onOpen() {
  var ui = SpreadsheetApp.getUi();
  ui.createMenu('Custom Tools')
      .addItem('Remove Blank Rows', 'removeBlankRows')
      .addToUi();
}

function removeBlankRows() {
  var sheet = SpreadsheetApp.getActiveSpreadsheet().getActiveSheet();
  var range = sheet.getDataRange();
  var values = range.getValues();
  var rowsToDelete = [];

  // Loop through all rows and check for blank rows
  for (var i = values.length - 1; i >= 0; i--) {
    var isBlank = values[i].every(function(cell) { return cell === ''; });
    if (isBlank) {
      rowsToDelete.push(i + 1);
    }
  }

  // Delete rows in reverse order to avoid shifting indices
  for (var j = 0; j < rowsToDelete.length; j++) {
    sheet.deleteRow(rowsToDelete[j]);
  }
}