ci(kernel-e2e): bump KERNEL_REV to current kernel main

The original pin (aed2efb) predates kernel PR #36 which added
`complex_types_as_json` to Session.__new__. Connector main already
passes that kwarg (added in PR #795), so every e2e test was failing
with:

  TypeError: Session.__new__() got an unexpected keyword argument
  'complex_types_as_json'

Bump to current kernel main (3aa25b21) which has the kwarg plus the
rest of the comparator-parity changes the connector code already
expects.

This is a good demonstration of why the bisectable KERNEL_REV pin
matters: the connector and kernel evolved in lockstep on `main`
before this CI existed, so the very first thing the workflow does
once it can actually build the wheel is catch that we'd been
shipping a stale pin.

Co-authored-by: Isaac
Signed-off-by: Vikrant Puppala <vikrant.puppala@databricks.com>

Author: vikrantpuppala

KERNEL_REV

@@ -1 +1 @@
-aed2efbed8087171d61848f5ad98c7e171827698
+3aa25b219ac4ec2c1e95c6f836b67d5475ae9a7d