Show dialog to select customizations

[pras0131]

Reference ticket: https://issues.amazon.com/issues/ECLIPSE-294

• The PR aims to show the Select Customization option in the menu bar, and clicking on the same opens up a dialog to select customizations.
• Right now, the implementation of Pro Login via IAM Identity control center does not exist, so the visibility of the customization menu option & the corresponding dialog has been put behind just isLogin condition (which checks the login via BuilderID)
• A little about functionality and some edge cases in the PR: The dropdown will be disabled if Amazon Q Foundation (default) is selected. Option to select the customisation (from dropdown) is only enabled when customization radio button is selected. The existing DialogContributionItem has not been used, because we need to do some pre-action before opening up the dialog like making a call to the LSP to fetch the list of customizations and setting the initial state of radio button (or pre-chosen customization in case of customization radio button) auto selection based on the saved preferences.
• Selected customization will be saved in the Preference Store. Preference store customization configuration will be deleted if the user selects the default configuration, which is Amazon Q Foundation.
• Right now, there is no call to LSP to fetch the configurations. Currently the response is mocked..Call to LSP to fetch the customizations will be done in a separate PR. Also, right now pressing Select option saves the preference in a preference store but notification to LSP on change of configuration will be done separately in a different PR.
• Attaching the screenshots below for reference:

[breedloj]

Is the screenshot up to date and is the dialog now reflecting Jo's latest comments?

[pras0131]

Is the screenshot up to date and is the dialog now reflecting Jo's latest comments?

Updated the screenshot and fixed the UI based on Jo's latest comments.