Merge #21728: remove executable flag for src/net_processing.cpp

f2f2541 remove executable flag for src/net_processing.cpp (Sebastian Falbesoner)

Pull request description:

  The file permissions for `src/net_processing.cpp` have been changed in #21713, as discovered by fanquake (bitcoin/bitcoin#21713 (comment)). This PR removes the executable flag again.

ACKs for top commit:
  kiminuo:
    ACK f2f2541 :)
  jnewbery:
    ACK f2f2541
  promag:
    ACK f2f2541.

Tree-SHA512: 1d5a62afb1152029e69fccea2ae53dcb262a91724a5c03dfc4de8c409b280814d0c211c2f9a71f1a6e927f4ed571ba4ac311de9de8ebb797eaf1051674241bdb

Author: fanquake