Remove more useful type information for mypy

Author: jessegrabowski

pytensor/tensor/slinalg.py

@@ -11,7 +11,6 @@
 
 import pytensor
 import pytensor.tensor as pt
-from pytensor import Variable
 from pytensor.gradient import DisconnectedType
 from pytensor.graph.basic import Apply
 from pytensor.graph.op import Op
@@ -1715,7 +1714,7 @@ def perform(self, node, inputs, outputs_storage):
         fn = scipy_linalg.get_blas_funcs("gbmv", dtype=A.dtype)
         outputs_storage[0][0] = fn(m=m, n=n, kl=kl, ku=ku, alpha=1, a=A_banded, x=x)
 
-    def L_op(self, inputs, outputs, output_grads) -> list[Variable]:
+    def L_op(self, inputs, outputs, output_grads):
         # This is exactly the same as the usual gradient of a matrix-vector product, except that the banded structure
         # is exploited.
         A, x = inputs