4ffc6641b7
Fixes: #9614
Issue link: https://github.com/spring-projects/spring-integration/issues/9614
The `Matcher.quoteReplacement()` escapes `\` as well as `$`.
However, Jackson tries to resolve special symbol from the escaped `$` and fails as `Unrecognized character escape '$' (code 36)`
* Fix `SimpleJsonSerializer.toElement()` to escape only `\`
(cherry picked from commit 8dad15bac2)