[API tests] Separate APIV1 fixture and verification reliability fixes

[Prangshuman Das (t-prda)]

Scope

AB#646383

Draft follow-up to #11230, based on prdas/646383-split-return-shipment-pdf.

• Identify five posted blank API lines by GUID description and exact record lookup.
• Regenerate RapidStart fixtures per invocation; refresh all three polling loops, correct expected/actual assertion order, and fix the apply-status qualifier.
• Keep G/L journal-template handler state in a codeunit global.
• Enable Foundation setup for the invoice discount-percent scenario.
• Re-enable exactly ten APIV1 methods temporarily quarantined while these business fixes were separated. These were conservative/deferred exclusions, not newly proven failures. RS create/upload were not additionally quarantined.

Lifetime and preservation

Automation initialization keeps workdate first, followed by idempotent authentication-provider selection, per-test cleanup, and sample generation. Removing the guard makes provider selection per invocation; its existing same-provider early return remains intact.

Preserves all seven earlier layers, APIV2 wildcards, and all 22 Expense exclusion entries. Only eight AL files and the APIV1 exclusion manifest change.

Validation

• Static context-patch and reviewed-method equivalence checks passed.
• Exact nine-file scope, protected-manifest byte equality, and git diff --check passed.
• This stacked head remains runtime untested. Prerequisite [Expense Agent tests] Fix action-result assertions for runtime compilation #11340 has resolved the CU 148339 compilation blocker; that success does not validate this layer. The RapidStart polling tests require background task execution and a compatible validation profile. No local NST was used.

Linked to native GitHub stack #11232: #10085 is the bottom auth PR, followed by #11224 through #11230, then this draft as the top layer. All eight follow-ups are drafts. No branch was force-pushed and no PR was merged. The first seven layers restore 37 deferred methods; this layer restores the remaining ten, preserving pre-existing exclusions.