Prompt user to provide the credentials

I would like to show the a prompt/popup/daialouge box that will ask user to provide the credentials.

I am using power bi desktop and powerbi cloud service.

I am working on a report that collects data from rest api, which needs to be autheticated.

I have created two parameters UserName and Password and using same within power query. 

Here is the query I have formed. In the data source settings I have set the authetication as Basic.

let
Source = Username & ":" & Password,
Bytes = Text.ToBinary(Source),
TextForm = Binary.ToText(Bytes, BinaryEncoding.Base64),

url = "API URL",

GetJson = Json.Document(Web.Contents(url,
[
Headers = [#"Content-Type"="application/json",#"Authorization"="Basic " & TextForm]

])),

#"Converted to Table" = Record.ToTable(GetJson),
Value = #"Converted to Table"{2}[Value],
#"Converted to Table1" = Table.FromList(Value, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
#"Expanded Column1" = Table.ExpandRecordColumn(#"Converted to Table1", "Column1", {"Id", "Name", "Salary"},
{"Column1.Id", "Column1.Name", "Column1.Salary"}),
#"Renamed Columns" = Table.RenameColumns(#"Expanded Column1",{{"Column1.Id", "EMPID"}, {"Column1.EMPName", "EMPName"}, {"Column1.Salary", "Salary"}})
in
#"Renamed Columns"

While refresh the report or reopen of report, no prompt box is there. I observed that query stores the user name and password provided in datasource settings.

Is there a way  to prompt the user for credentials and get the provided input into paramaters? like username and password.