NIFI-16157: Add millis to formatDurationToWords

[ohnoitsyou]

Missed adding 'ms' to the initial implementation.

Updated implementation to include down to seconds by default and include
sub-seconds if present

Sub-seconds follow reverse, higher units included if lower unit present

Summary

NIFI-16157

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  • JDK 21
  • JDK 25

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Documentation

• Documentation formatting appears as expected in rendered files

[exceptionfactory]

Thanks for this improvement @ohnoitsyou! +1 merging