fix(ai-agents): Remove outdated size limits (#16315)

Author: alexander-alderman-webb

develop-docs/sdk/telemetry/traces/modules/ai-agents.mdx

@@ -237,9 +237,3 @@ Some attributes are common to all AI Agents spans:
 | `"openai"`          | OpenAI                            |
 | `"perplexity"`      | Perplexity                        |
 | `"xai"`             | xAI                               |
-
-## Size Limits
-
-In addition to the [general size limits](https://docs.sentry.io/concepts/data-management/size-limits/) for events, spans, and attachments, there are specific size limits for AI integrations:
-
-- Input messages in AI integrations recorded in the span attribute `gen_ai.input.messages` (or the deprecated `gen_ai.request.messages`) are limited to 20kB per span. Messages are trimmed and truncated if they exceed the limit, retaining the most recent messages.