Use CopyableField component in Issue Sidebar email address component

What does this MR do?

Follow-up to !5682 (closed). Uses the new copyable_field.vue component for the presentation of copy_email_to_clipboard.vue.

Additionally, copyable_field has a new prop: clipboardTooltipText, to allow the developer to set custom tooltip text for the clipboard button (in this case, Copy email address).

Related Issue: #324610 (closed)

Screenshots (strongly suggested)

Screenshots demonstrate no user-facing change

Before	After

Does this MR meet the acceptance criteria?

Conformity

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  • I have included a changelog entry.
  • I have not included a changelog entry because this is a ~"feature::maintenance" change.
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Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
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