deps: update to confluent-kafka 2.14.0

[amotl]

Problem

An old version of confluent-kafka blocks fluent wheel-based installation on Python 3.14 (without needing a compiler toolchain and development headers from librdkafka-dev).

Details

      fatal error: librdkafka/rdkafka.h: No such file or directory
         23 | #include <librdkafka/rdkafka.h>
            |          ^~~~~~~~~~~~~~~~~~~~~~
      compilation terminated.
      error: command '/usr/bin/gcc' failed with exit code 1

References

• CI: Use more Python 3.14 (next) crate/cratedb-toolkit#592 (CI failure)

/cc @turtleDev, @iremcaginyurtturk

[amotl]

Hi @turtleDev. The previous CI run failed because of other reasons. Can you permit another run?