Pipeline Graph: Namespace translations in view switcher for clarity

What does this MR do?

Adds a namespace to the toggle translations in response to notes about incorrect translation for Stage in German. (See #333594 (closed))

Screenshots (strongly suggested)

Says Stage instead of Vormerken in German.

Does this MR meet the acceptance criteria?

Conformity

• I have included changelog trailers, or none are needed. (Does this MR need a changelog?)
• I have self-reviewed this MR per code review guidelines.
• This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.
• This change is backwards compatible across updates, or this does not apply.

Related to #333594 (closed)