Remove dead provides from pipeline editor app

What does this MR do?

Removes the dead Vue provides from the pipeline editor entrypoint (app/assets/javascripts/ci/pipeline_editor/options.js) — all injected by no component.

Provide	Action	Why
helpPaths	Full removal (JS + Jest mock)	Phantom — the help-paths data attribute was never set by the helper.
lintHelpPagePath	Full removal (JS + helper + spec)	Inline value in js_pipeline_editor_data, injected nowhere.
pipelinePagePath	Full removal (JS + helper + spec)	Same.
projectPath	Full removal (JS + helper + spec)	Same. (Distinct from the in-use projectFullPath, which stays.)
projectNamespace	Full removal (JS + helper + spec)	Same.
dataMethod	Provide entry only	Hardcoded 'graphql' constant, no data attribute.
defaultBranch	Provide entry only	Injected nowhere, but the entrypoint still reads the dataset value to seed the Apollo current-branch cache, so the default-branch attribute and dataset read stay.

Why now?

With the introduction of !242236 (merged) I was able to remove unused injects in our files (this is quite automatic). However, that leaves dangling provides that can't be so easily cleaned up.

How I verified

• Confirmed no pipeline_editor component injects any of these (the two the tool marked "inconclusive" — defaultBranch, projectPath — are not injected anywhere in the editor tree; the inconclusive verdict came from unrelated monaco-editor external-import boundaries).
• yarn eslint clean; rubocop clean on the helper.
• yarn jest spec/frontend/ci/pipeline_editor/options_spec.js green; rspec spec/helpers/ci/pipeline_editor_helper_spec.rb green (8).
• Re-ran the trace: 0 removal candidates remain (16 provides).
• Visual check via spec/features/projects/ci/editor_spec.rb — the page renders correctly after the removal (no missing-injection errors). The default-branch dataset read is kept, so the branch switcher still shows the current branch:

Edit tab (branch switcher shows current branch)

Visualize tab (valid CI renders the graph)

Notes for reviewers

Frontend dead-code cleanup that also trims the js_pipeline_editor_data helper + its spec; no changelog. Scoped to the one provider file and its helper.