Rename some variables in NsdService

- This is a no-op change change that only unify the naming of
  transaction IDs. Because there are currently different naming
  conventions for transaction IDs, which can cause confusion and
  lead to errors.
- Also renaming the "client ID" to "client request ID" because
  this more accurately reflects how the ID is used.

Bug: 287546772
Test: m
Change-Id: I4fb7255f23754aa720a83a5df282700c59140207
1 file changed