Update size each time to ensure correct data copy in If node (#34971)
### Details:
- *PortMapHelper initializes the size to 0 during construction and
refresh it only inside redefineTo at execution time. However, when the
runtime shape is static, redefineTo may be skipped, leaving the size at
0 and causing cpu_convert to use an incorrect element count.*
- *This PR updates the size from srcMemPtr shape on every redefineTo
call, ensure that cpu_convert always receives the correct size*
### Tickets:
- *CVS-183109*