Fix slash in bundle/integration_whl acceptance tests (#3216)

## Changes
Reverts: #3195

## Why
These tests started failing because of the missing repl. Diff:
```
->>> cp [TESTROOT]/bundle/resources/clusters/run/spark_python_task/../../deploy/simple/hello_world.py .
+>>> cp [TESTROOT]\bundle\resources\clusters\run\spark_python_task/../../deploy/simple/hello_world.py .
```

Author: shreyas-goenka

acceptance/bundle/integration_whl/serverless/test.toml

@@ -3,3 +3,7 @@ Local = false
 
 # serverless is only enabled if UC is enabled
 RequiresUnityCatalog = true
+
+[[Repls]]
+Old = '\\'
+New = '/'

acceptance/bundle/integration_whl/serverless_dynamic_version/test.toml

@@ -1,2 +1,6 @@
 # serverless is only enabled if UC is enabled
 RequiresUnityCatalog = true
+
+[[Repls]]
+Old = '\\'
+New = '/'