The Accton-AS4625-54T uses alias format Eth1(Port1) instead of the
standard tenGigE1 format. The inline regex r"(\d+)$" failed to extract
port numbers from this format because the string ends with ")" not a digit,
causing NetBox interface mapping to fail and ports to appear disconnected.

Solution: Replace inline regex with existing _extract_port_number_from_alias()
helper function which correctly handles both formats:
- Standard format: tenGigE1 -> extracts 1
- AS4625-54T format: Eth1(Port1) -> extracts 1

This allows proper NetBox to SONiC interface mapping:
  Eth1(Port1) -> generates expected_names ['Eth1/1', 'Eth1/1/1']
  -> matches NetBox interface Eth1/1 -> returns Ethernet0

Result: AS4625-54T ports are now correctly detected as connected,
receive admin_status='up', and have BGP configurations generated.

AI-assisted: Claude Code

Signed-off-by: Christian Berendt <berendt@osism.tech>