1.4.4: outlier filter on by default for new installs

Soak feedback from an 18-day production run on cwv 1.0.1 (~554
beacons) surfaced a 596876ms FCP beacon — a 9.9-minute value
from a backgrounded-tab artefact — landing in storage and
dragging the metric's p75 around.

The outlier filter that catches this class of event already
shipped in 1.1.0 (outlier_filter_enabled with per-metric
thresholds defaulting to LCP/FCP 30000ms, INP 5000ms, TTFB
60000ms, CLS 5), but was opt-in. The opt-in posture was
deliberate at 1.1.0 to avoid silently shifting distributions
for existing operators on upgrade, but that argument doesn't
apply to new installs.

1.4.4 flips outlier_filter_enabled to true in
config/install/cwv.settings.yml. Existing installs keep
whatever they had (config-install runs once at module install
time; upgrade is a no-op). New installs from 1.4.4 onwards get
the safer default automatically.

No update hook. No schema change. No behaviour change for
upgraders who hadn't already toggled the filter on. Form
description updated to reflect the new posture and list the
default thresholds inline so the operator can audit them
without expanding the fieldset.

Library version bump 1.4.3 -> 1.4.4 (cache-busts the JS asset).

ROADMAP also updated to record the 1.4.1 - 1.4.3 correctness
patch chain and to note that 1.5.0 will include the
probe-onboarding hook_requirements warnings flagged by the
same soak.

First release where the d.o. CI pipeline is genuinely green
across all seven jobs from the first run, no allow_failure
crutches and no follow-up commit needed.