Allow numeric to be tampered in FindReplace & sprintf functions

Problem/Motivation

Find/Replace functions have a test to verify that the data is a string before acting on it. However when you try to parse an ID inside a feed and match it to a taxonomy term, the integer data will return an error "Input should be a string".

Steps to reproduce

Try to add a plugin FindReplace to a JSON feed with integer ID to match an existing taxonomy term name.

"category": {
  "id": 123,
  "label": "Feed category name "
},

So here we would like to replace 123 by our existing Taxonomy term "Website category A" so the match can be done whenever the label in the field would change.

Proposed resolution

Make a broader test to include numerics for those tests :

    if (!is_string($data)) {
      throw new TamperException('Input should be a string.');
    }

Also should booleans be allowed too ?

Remaining tasks

Patch to review

User interface changes

None

API changes

None

Data model changes

None