chore(deps): drop Google's libphonenumber, use the Android port everywhere

[bmc08gt]

Why

The app depended on two libphonenumber artifacts:

Artifact	Used by
io.michaelrocks:libphonenumber-android (the Android port)	:shared:phone, :shared:onramp:coinbase
com.googlecode.libphonenumber:libphonenumber (Google's desktop artifact)	:shared:onramp:coinbase, plus 3 dead declarations

Each ships its own copy of the metadata, so any version skew between them meant the two could disagree on whether a number is valid. The port lags upstream, so it always set the ceiling — which is why the catalog carried a "keep these pinned together" comment and a Dependabot group rule. In practice that just blocked routine bumps: #1259 was a Google-only 9.0.37 that the port had not published yet.

Dropping the Google artifact removes the skew risk and the pin.

What changed

Three of the four Google declarations were dead. :services:flipcash, :services:flipcash-compose and :services:opencode each declared it, but have no Kotlin imports of it and no references to i18n/phonenumbers anywhere in their compiled output (build/tmp/kotlin-classes, build/intermediates/javac, build/generated). The catalog comment claimed "the services modules validate with Google's artifact" — that code does not exist. Removed.

The one real consumer is ported. PhoneRegion.regionFromPhone in :shared:onramp:coinbase moves to the Android artifact. That artifact loads its metadata from the AAR's assets instead of exposing a static getInstance(), so it needs a Context — the top-level function becomes an injectable PhoneRegionResolver, mirroring PhoneUtils in :shared:phone, lazy PhoneNumberUtil included so the metadata blob is parsed on first use rather than during construction on the main thread.

The test moves to Robolectric for that Context. Its 13 cases and their expected values are deliberately unchanged — they are the parity check that the port agrees with Google's artifact on every number covered.

With the Google artifact gone, the Dependabot group rule that kept the two aliases in lockstep is no longer needed.

Verification

• :shared:onramp:coinbase:test :shared:phone:test :services:flipcash:test — BUILD SUCCESSFUL; PhoneRegionTest reports tests="13" failures="0" errors="0"
• :apps:flipcash:app:assembleDebug — BUILD SUCCESSFUL
• Resolved debugRuntimeClasspath: zero com.googlecode.libphonenumber entries; io.michaelrocks:libphonenumber-android:9.0.36 only

Note on regionFromPhone

It currently has no production callers — only its own test. CoinbaseOnrampApi has the matching subdivision query param, so it was built for a call that was never wired up. Ported rather than deleted, to keep that option open.

Relationship to #1269

#1269 added an ignore rule for com.googlecode.libphonenumber:libphonenumber 9.0.37 as a stopgap, and has since merged. This PR removes that rule along with the group rule — with the artifact gone from the build entirely, there is nothing left for either to act on.