Upgrade abavalidator from ^2.0.2 to ^3.1.2

[francescouph]

abavalidator dependency is behind latest version (3.1.2)
Other repos, such as bank-gateway have abavalidator@3.1.2 as direct dependency .

because of the explicit dependency, abavalidator is deduped, meaning that is.abaRoutingNumber() in bank-gateway is using abavalidator@3.1.2 already:

❯ yarn why abavalidator
yarn why v1.22.22
warning ../../../package.json: No license field
[1/4] 🤔  Why do we have the module "abavalidator"...?
[2/4] 🚚  Initialising dependency graph...
[3/4] 🔍  Finding dependency...
[4/4] 🚡  Calculating file sizes...
=> Found "abavalidator@3.1.2"
info Has been hoisted to "abavalidator"
info Reasons this module exists
   - Specified in "dependencies"
   - Hoisted from "@uphold#jpmc-client#abavalidator"
info Disk size without dependencies: "76KB"
info Disk size with unique dependencies: "76KB"
info Disk size with transitive dependencies: "76KB"
info Number of shared dependencies: 0

Preliminary Claude check suggests the major bump to have no breaking changes:

- The API is unchanged — require('abavalidator').validate(routingNumber) still returns a boolean, same as in v2. Let's quickly run the existing test suite to confirm behavior didn't change.

- No breaking changes. Summary:
  - abavalidator 2.0.2 → 3.1.2 only changed internals (TypeScript rewrite, build tooling, minified browser bundle path). The public API is identical: require('abavalidator').validate(routingNumber:
  string): boolean.
  - aba-routing-number-assert.js uses exactly that call and needs no changes.
  - Existing tests (test/asserts/aba-routing-number-assert.test.js) pass unmodified against v3.1.2.

Regardless, given the major bump of a validator dependency, we should to do a major release if this PR is merged.

[josecarlosbrandao]

LGTM, lets just deploy this branch temporarily to CONN and execute an ACH transaction to make sure it doesnt break anything in our flows (it shouldn't from what i saw 😄)