Fix component bugs found during the TypeScript migration

[mdo]

Stacked on #42724 (targets its branch, not v6-dev). Fixes latent bugs surfaced while migrating the JS to TypeScript — each was documented in that PR and left unchanged there to keep the migration byte-identical.

• tooltip: compare Floating UI arrow coordinates against undefined (the value the arrow middleware actually reports) instead of null, so an absent cross-axis coordinate no longer writes left: "undefinedpx". Also adapt an offset callback's [skidding, distance] array return into Floating UI's { mainAxis, crossAxis } shape, matching the array/string config forms.
• dialog: remove the unnamespaced native cancel listener on dispose() — BaseComponent.dispose() only clears EVENT_KEY-namespaced listeners, so it previously leaked past teardown. (Left unnamespaced because cancel is a native event, not one of our namespaced custom events.)
• nav-overflow: namespace the fallback window resize listener and remove it on dispose(); drop the write-only _isInitialized flag.
• chips: remove only a single value entry on remove() so duplicate chips stay in sync with the DOM when allowDuplicates is enabled (previously filter stripped every matching value from state while one element remained).
• strength: drop the unused score argument passed to _updateUI (the meter fill derives from strength).
• toggler: document that value is required — the null default is a must-override placeholder and DefaultType intentionally rejects it.

Adds unit coverage for each fix, including a new chips.spec.js (chips had no prior tests); keeps the global branch-coverage gate satisfied. Built dist/js/dist rebuilt in a separate commit.

A further latent bug found along the way — the change.bs.chips event name colliding with the native change event so listeners never receive it — is left for a separate PR as it needs an event rename.