chore(validation): Remove experimental validation call

[wmak]

• This endpoint was experimental and we're removing it in favour of a planned validate endpoint that will look at the entire query instead of just the attributes
• Removing this since currently everyone hitting is just getting a 403 anyways

[sentry-warden]

Tool inputSchema advertises attributes validation parameter that is never consumed after removing validation logic

The attributes parameter remains in the exported inputSchema with description "Optional exact attribute keys to validate" but its value is destructured and silently ignored in the execute function, so clients/models will supply it expecting validation that no longer occurs. The tool-level description also still claims it can "validate" attributes. Remove the parameter and update the description, or restore validation logic.

Evidence

• attributes is declared in the tool's Zod parameters schema (utils.ts:466-472) with description "Optional exact attribute keys to validate, such as ['tags[type]', 'span.duration']".
• In the execute handler (utils.ts:474-480) attributes is destructured from params but is never passed to fetchCustomAttributes (which only receives attributeTypes, substringMatch, query) nor used anywhere in the function body.
• traceItemType is computed via getTraceItemType(normalizedDataset) but never used, indicating leftover code from the now-removed validation path.
• The tool-level description still says "Query, filter, and validate available attributes", so the exported wire metadata misrepresents the tool's actual behavior to the model.

_{Identified by Warden mcp-audit · WDB-XU9}