Fix issue #4422, #4424

[nqviet]

#4422

1. When there is only one milestone, at that time it is not accessible in customer view
   --- This is normal behaviour, Draft milestone won't be visible to customer.
2. Let's update content of message from PHASE > Milestone
   --- Fixed in alert message text
3. Let's show dropdown instead of normal textbox
   --- Fixed UI issue
4. Let's remove Action column for Customer View
   --- Fixed
5. Let's validate one row at a time.
   --- Fixed: validator functions are called only for an active row
6. System is taking duplicate milestone name (typing space at the end of text )
   --- Fixed: trim value before comparing

#4424
--- Fixed: Add non negative validator for budget value