"A few minor fixes, and an improvements in the cost function of the routing algorithm."

What's new:

• Plugins: pay route algorithm doesn't bias against our own "expensive" channels any more. (#7127)
• pay: Prevent repeating the preapproveinvoice check (#7121)
  Plugins: pay would occasionally crash on routing. (#7127)
• Plugins: pay route algorithm fixed and refined to balance fees and capacity far better. (#7127)
  renepay: bugfix situation with htlcmax=htlcmin