Ensure that the replace() SQL function always returns a TEXT value even

when its first argument is numeric and its second argument is an empty string.
Fix for the issue reported by
[forum:/forumpost/3776b48e71|forum post 3776b48e71].

FossilOrigin-Name: 01868ebcd25fadb2034da234c0636e82d07c5abc902ef66493cadfc988e74d7b