fix(vue2): Vuex: trim namespace for getter's path if it is not namespaced

[Azurewarth0920]

Description

fix: #2031
When calculating the path of the getters, the non-namespaced should be trimmed.
This PR will trim the path properly

Eg.

• ParentModule (non-namespaced)
  • ChildModule (name-spaced)

The path as is: ParentModule/ChildModule/
The path to be: ChildModule/

Additional context

---

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

Before submitting the PR, please make sure you do the following

• Read the Contributing Guidelines.
• Read the Pull Request Guidelines and follow the Commit Convention.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).