feat(multilanguage): switch template language method

[simcen]

Description

Adds type specifications for switchTemplateLanguage method

Motivation and Context

Fully leverage multi language templates

Usage examples

import BeePLugin from '@mailupinc/bee-plugin'

const beePlugin = new BeePlugin()
beePlugin.getToken()

const beeConfig :IBeeConfig = {
templateLanguage: { value: "de-DE", label: "Deutsch" },
  templateLanguages: [
      { value: "de-DE", label: "Deutsch" },
      { value: "fr-FR", label: "Français" },
      { value: "it-IT", label: "Italiano" }
  ],
}

beeTest.switchTemplateLanguage({language: "de-DE"});

How Has This Been Tested?

Extended example application with a language switcher that executes switchTemplateLanguage({language: "de-DE"}) on the bee instance

Types of changes

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

[pinkynrg]

This update has just been released in version 3.1.0. In addition to your modification, we've also included the "switchPreview" method to enable language switching while in preview mode.

Closing.