Merge bitcoin/bitcoin#22002: Fix crash when parsing command line with -noincludeconf=0

fad0867d6ab9430070aa7d60bf7617a6508e0586 Cleanup -includeconf error message (MarcoFalke)
fa9f711c3746ca3962f15224285a453744cd45b3 Fix crash when parsing command line with -noincludeconf=0 (MarcoFalke)

Pull request description:

  The error message has several issues:

  * It may crash instead of cleanly shutting down, when `-noincludeconf=0` is passed
  * It doesn't quote the value
  * It includes an erroneous trailing `\n`
  * It is redundantly mentioning `"-includeconf cannot be used from commandline;"` several times, when once should be more than sufficient

  Fix all issues by:
  * Replacing `get_str()` with `write()` to fix the crash and quoting issue
  * Remove the `\n` and only print the first value to fix the other issues

  Before:

  ```
  $ ./src/bitcoind -noincludeconf=0
  terminate called after throwing an instance of 'std::runtime_error'
    what():  JSON value is not a string as expected
  Aborted (core dumped)

  $ ./src/bitcoind -includeconf='a b' -includeconf=c
  Error: Error parsing command line arguments: -includeconf cannot be used from commandline; -includeconf=a b
  -includeconf cannot be used from commandline; -includeconf=c
  ```

  After:

  ```
  $ ./src/bitcoind -noincludeconf=0
  Error: Error parsing command line arguments: -includeconf cannot be used from commandline; -includeconf=true

  $ ./src/bitcoind -includeconf='a b' -includeconf=c
  Error: Error parsing command line arguments: -includeconf cannot be used from commandline; -includeconf="a b"
  ```

  Hopefully fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=34493

  Testcase: https://github.com/bitcoin/bitcoin/files/6515429/clusterfuzz-testcase-minimized-system-6328535926046720.log

  ```
  FUZZ=system ./src/test/fuzz/fuzz ./clusterfuzz-testcase-minimized-system-6328535926046720.log
  ```

  See https://github.com/bitcoin/bitcoin/blob/master/doc/fuzzing.md

ACKs for top commit:
  sipa:
    utACK fad0867d6ab9430070aa7d60bf7617a6508e0586

Tree-SHA512: b44af93be6bf71b43669058c1449c4c6999f03b5b01b429851b149b12d77733408cb207e9a3edc6f0bffd6030c4c52165e8e23a1c2718ff5082a6ba254cc94a4

0 files changed, 0 insertions, 0 deletions