chore: update Vue Storefront core packages to 2.7.0

[fpdrozd]

The breaking change here is the required export of init function in the index.server.ts file. With this update the api client (axios in our case) will only be initialized once and not on each request to the api server.

Description

Related Issue

Motivation and Context

How Has This Been Tested?

Tested by performing a checkout pass.

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.