[Bug]: Import of "User defined Java expression" (Janino) from kettle is converting the formula-Field wrong

### Apache Hop version?

2.8

### Java version?

jdk-11.0.19.7-hotspot

### Operating system

Windows

### What happened?

I converted a bunch of Transformations from kettle files to HOP files using tha hop-import.bat.
The most Part is converted just fine, but the "User defined Java expression" (Janino) don't show the formula.
This is due an error in the conversion, where the node is converted in \.
This is not correct. It should still be .
This seems to be related to the changes in the Formula Transform:
https://github.com/apache/hop/blob/7330fa21d9f4317cdf05d66ea315758caec3c382/plugins/misc/import/src/main/java/org/apache/hop/imports/kettle/KettleConst.java#L73

### Issue Priority

Priority: 2

### Issue Component

Component: Import

Start in plugins/misc/import/src/main/java/org/apache/hop/imports/kettle/KettleConst.java at the referenced conversion mapping, then inspect how hop-import.bat handles the Kettle “User defined Java expression” transform. Reproduce the conversion with a formula_string field and verify that the generated HOP file preserves the formula_string node so the formula appears in the imported transform.

Written by the indexing model from the issue text.