build(plugin-keychain-memory): fix local imports broken due to .js extensions

[petermetz]

Description

Reproduce by executing this on main:

yarn jest packages/cactus-plugin-keychain-memory/src/test/typescript/integration/api-surface.test.ts
and then watch it fail as such:

$ yarn jest packages/cactus-plugin-keychain-memory/src/test/typescript/integration/api-surface.test.ts
jest-haste-map: duplicate manual mock found: ConfigUtil
  The following files share their name; please delete one of them:
    * <rootDir>/packages/cactus-cmd-socketio-server/src/main/typescript/routing-interface/util/__mocks__/ConfigUtil.ts
    * <rootDir>/packages/cactus-cmd-socketio-server/dist/lib/main/typescript/routing-interface/util/__mocks__/ConfigUtil.js

 FAIL  packages/cactus-plugin-keychain-memory/src/test/typescript/integration/api-surface.test.ts
  ● Test suite failed to run

    Cannot find module './default_service_pb.js' from 'packages/cactus-plugin-keychain-memory/src/main/typescript/generated/crpc/services/default_service_connect.ts'

    Require stack:
      packages/cactus-plugin-keychain-memory/src/main/typescript/generated/crpc/services/default_service_connect.ts
      packages/cactus-plugin-keychain-memory/src/main/typescript/plugin-keychain-memory.ts
      packages/cactus-plugin-keychain-memory/src/main/typescript/public-api.ts
      packages/cactus-plugin-keychain-memory/src/test/typescript/integration/api-surface.test.ts

      13 | // @ts-nocheck
      14 |
    > 15 | import { DeleteKeychainEntryV1Request, GetKeychainEntryV1Request, GetPrometheusMetricsV1Response, HasKeychainEntryV1Request, SetKeychainEntryV1Request } from "./default_service_pb.js";
         | ^
      16 | import { DeleteKeychainEntryResponseV1PB } from "../models/delete_keychain_entry_response_v1_pb_pb.js";
      17 | import { Empty, MethodKind } from "@bufbuild/protobuf";
      18 | import { GetKeychainEntryResponseV1PB } from "../models/get_keychain_entry_response_v1_pb_pb.js";

      at Resolver._throwModNotFoundError (node_modules/jest-resolve/build/resolver.js:427:11)
      at Object.<anonymous> (packages/cactus-plugin-keychain-memory/src/main/typescript/generated/crpc/services/default_service_connect.ts:15:1)
      at Object.<anonymous> (packages/cactus-plugin-keychain-memory/src/main/typescript/plugin-keychain-memory.ts:26:1)
      at Object.<anonymous> (packages/cactus-plugin-keychain-memory/src/main/typescript/public-api.ts:4:1)
      at Object.<anonymous> (packages/cactus-plugin-keychain-memory/src/test/typescript/integration/api-surface.test.ts:1:1)

Test Suites: 1 failed, 1 total
Tests:       0 total
Snapshots:   0 total
Time:        0.61 s
Ran all test suites matching /packages\/cactus-plugin-keychain-memory\/src\/test\/typescript\/integration\/api-surface.test.ts/i.

Acceptance Criteria

1. Fix the generated code which appears to be importing .js extension files OR fix the Jest config whichever turns out to be the solution that doesn't add more tech. debt.