Remove dead legacy blame frontend entrypoints

What does this MR do and why?

This MR is one of in the series related to #618439 (closed).

This MR removes dead JavaScript entrypoints and bundle files that no longer mount on any current page.

Code that stays in place:

• app/assets/javascripts/blame/preferences/blame_preferences.vue remains because app/assets/javascripts/blob/components/blame_header.vue mounts it in the inline blame experience.
• app/assets/javascripts/blame/blame_legend.vue remains for the same reason.

References

• #618439 (closed) (Follow-up issue: Remove the legacy Blame page)
• !257407 (merged) (Dependency MR: Remove inline_blame feature flag)
• !257918 (merged) (Sibling MR A: Remove the legacy blame ?page= query param)
• !257919 (merged) (Sibling MR B: Retire the legacy blame page actions and routes)

These three MRs touch no files in common and can be reviewed in parallel.

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