fallback locale deep key using tm throw error

[everyx]

Reporting a bug?

When a deep not exist current locale, but exist in fallback locale, it will throw error Cannot read properties of null (reading 'xxx')

Expected behavior

Use the value from the fallback locale

Reproduction

https://stackblitz.com/edit/vitejs-vite-zkwein?file=src%2FApp.vue,src%2Fmain.ts

System Info

System:
    OS: Linux 5.0 undefined
    CPU: (4) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
    Memory: 0 Bytes / 0 Bytes
    Shell: 1.0 - /bin/jsh
  Binaries:
    Node: 18.18.0 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 10.2.3 - /usr/local/bin/npm
    pnpm: 8.14.0 - /usr/local/bin/pnpm
  npmPackages:
    @vitejs/plugin-vue: ^4.2.3 => 4.3.4 
    vite: ^4.4.9 => 4.4.9 
    vue: ^3.3.4 => 3.3.4 
    vue-i18n: ^9.3.0 => 9.3.0 
    vue-tsc: ^1.8.8 => 1.8.10

Screenshot

No response

Additional context

No response

Validations

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