how to delete a entire row in readOnly grid?

For this, you can create an extra column in gridfield and in that create a icon and use dynamic link to remove the row from the variable and if you want to remove it from DB then use deletefromdatastoreentity as well along with remove function.

please check code once,please verify index position

a!gridColumn(

                  label: "",

                  value: a!richTextDisplayField(

                    value: a!richTextIcon(

                      icon:"trash-o",

                      link:a!dynamicLink(

                        value: 'type!{urn:com:appian:types:HR}hrcandidatedetails'(),

                        saveInto:a!save(ri!hrcandidatedetails,remove(ri!hrcandidatedetails,fv!row)),

                      )

                  )

                ),

                ),

Remove works with the index and not the item. You will have to use the identifier (if the data is not DB backed) and wherecontains() if the data is DB backed in the second parameter of the remove() function. 

Expression evaluation error at function 'remove' [line 149]: Invalid index (3) for list: valid range is 1..1

please show me the code if possible for remove only

Do you only have one row in the grid?

I have multiple Rows, In that selected row to be deleted by using richTextIcon what we did in editable grid?

Try running this code in an unnamed interface to understand how removing works. 

a!localVariables(
  local!data: {
    { first: "Some", second: "Value" },
    { first: "Another", second: "Point" }
  },
  a!gridField(
    data: local!data,
    columns: {
      a!gridColumn(
        label: "First Column",
        value: fv!row.first
      ),
      a!gridColumn(
        label: "Second Column",
        value: fv!row.second
      ),
      a!gridColumn(
        value: a!richTextDisplayField(
          value: a!richTextIcon(
            icon: "times",
            link: a!dynamicLink(
              value: remove(
                local!data,
                wherecontains(
                  fv!row,
                  cast(typeof({ a!map() }), local!data)
                )
              ),
              saveInto: local!data
            )
          )
        )
      )
    }
  )
)

 in that applicationstatus filter  is ok  and Applied department & application status is not working at a time what we do?

Is this a new problem? If yes, please start a new thread for it. 
Do not mix up the threads. For the current thread, keep it only for deletion of the row. 
I added a code block, that should help you understand and implement it. 

yea sorry its ok