agent: don't print TURN password unless the logging is verbose

Limits accidental leakage of secret information.
6 jobs from master in 8 minutes and 44 seconds (queued for 12 seconds)
Status Job ID Name Coverage
  Build
passed #110653
build autotools

00:01:06

passed #110654
build meson

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  Test
passed #110656
distcheck autotools

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passed #110658
doc-and-install meson

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passed #110655
test autotools

00:02:43

passed #110657
allowed to fail
test meson

00:00:50