Re-enable AA0194 analyzer and obsolete unused DE/IT VAT return actions

[Onat Buyukakkus (onbuyuka)]

What & why

The AA0194 analyzer (an action must define an OnAction trigger or a RunObject property) was downgraded from Error to Warning in src/rulesets/base.ruleset.json. Under workspace compilation every project compiles against base.ruleset.json, so this override disabled the rule repo-wide. As a result a trigger-less action was able to ship and crash the web client when navigating to the Purchase Orders page.

This PR:

• Removes the AA0194 downgrade from base.ruleset.json, so it inherits Error from CodeCop.ruleset.json again (matching the convention that this file only lists deviations).
• Obsoletes the unused, hidden and inert actions: the DE/IT VAT return actions (VAT Return Period Card/List) and the DE ECSLReport Log Entries/Release/Reopen placeholders. All are Visible = false with no real OnAction body and hidden promoted actionrefs, so they are marked ObsoleteState = Pending (reason + ObsoleteTag = '29.0') and guarded with #if not CLEAN29, with their promoted actionrefs guarded to match. (For the ECSLReport actions the empty-body #pragma warning disable AA0194 is kept inside the guard, since the empty OnAction still trips the rule until they are removed in CLEAN29.)
• Suppresses the rule with #pragma warning disable AA0194 only on visible actions whose OnAction body is intentionally empty — removing a visible control would be a UI/compat change beyond this bug's scope: System PageDesigner PageFields View (functional; the empty body overrides default row behavior) and RU PostedFAWriteoffAct Dimensions/Comments (visible but with commented-out bodies — suppression preserves their existing behavior). This matches the existing pattern in Companies.Page.al.

Linked work

Fixes AB#645060

How I validated this

• I read the full diff and it contains only changes I intended.
• I built the affected app(s) locally with no new analyzer warnings.
• I ran the change in Business Central and confirmed it behaves as expected.
• I added or updated tests for the new behavior, or explained below why none are needed.

What I tested and the outcome

• Scanned all 36,464 .al files in src for actions that trigger AA0194 — both those lacking OnAction/RunObject and those whose OnAction body is empty (comments only, which the analyzer also flags). This surfaced 20 actions total: 15 hidden/inert actions now obsoleted (12 DE/IT VAT + 3 DE ECSLReport), 3 visible actions pragma-suppressed here (PageFields View, RU Dimensions/Comments), and 2 already suppressed in the repo. After the change the scan reports 0 unsuppressed AA0194 violations repo-wide.
• Verified base.ruleset.json still parses as valid JSON and that every edited page has balanced #if not CLEAN29 / #endif and matching #pragma warning disable/restore AA0194 pairs.
• Local build note: the changed files are country-layer pages with no standalone app.json; they are merged into the base app per country by the build pipeline, so they are not exercised by a single-project local build. Full per-country compilation with the re-enabled rule is validated by CI on this PR.
• No tests added: this is an analyzer ruleset configuration change plus page-metadata obsoletion. The analyzer itself is the enforcement mechanism; there is no runtime behavior to unit test.

Risk & compatibility

• AA0194 becomes a build Error again for all apps. The full-repo scan confirms the only current violations are the ones fixed here, so this should not break the build; any future trigger-less action will now fail fast (the intended safety net).
• The obsoleted actions (DE/IT VAT + DE ECSLReport) are already hidden (Visible = false) and inert, so obsoleting them has no functional or UI impact. Removal is deferred to CLEAN29; AL0432 (obsolete-pending usage) is None in the ruleset, so the guarded actionrefs produce no diagnostic.
• The pragma-suppressed actions are left exactly as they were (no behavior change): they are visible, so they are intentionally not removed. PageFields.View is functional; the RU Dimensions/Comments actions remain visible and inert as before (a pre-existing state) — this PR only silences the analyzer, it does not restore or remove them.