Fix Conv LHS packing padding/uninitialized ptrs V2 (#27215)
### Description
Refer to V1 of the fix here:
https://github.com/microsoft/onnxruntime/pull/27214
This PR includes all fixes from the V1 PR + logic to invalidate the lhs
cache pointers in case the pad buffer's underlying buffer has changed
due to a resize. The ARM team will look at potentially enhancing this
logic after the 1.24.0 release.
### Motivation and Context
Fix #26669
