Upgraded Vue to 2.6.10 and also Vuex to 3.1.0

What does this MR do?

Upgrades to the latest version of

    "vue": "^2.6.10",
    "vue-loader": "^15.7.0",
    "vue-template-compiler": "^2.6.10",
    "vue-virtual-scroll-list": "^1.3.1",
    "vuex": "^3.1.0",

What are the relevant issue numbers?

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated via this MR
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• Security reports checked/validated by reviewer