Updates EIS pricing link (#7308)

This PR updates the [EIS
pricing](https://www.elastic.co/docs/explore-analyze/elastic-inference/eis#pricing)
link to point to the serverless pricing table in Elastic Cloud
(https://cloud.elastic.co/cloud-pricing-table?productType=serverless)
instead of the previous serverless search pricing page.

Author: kosabogi

explore-analyze/elastic-inference/eis.md

@@ -216,7 +216,7 @@ You can now use `semantic_text` with the new ELSER endpoint on EIS. To learn how
 
 ## Pricing [pricing]
 
-All models on EIS incur a charge per million tokens. Certain LLM providers charge different prices depending on the prompt size. The pricing details are available on our [Pricing page](https://www.elastic.co/pricing/serverless-search).
+All models on EIS incur a charge per million tokens. Certain LLM providers charge different prices depending on the prompt size. The pricing details are available on our [Pricing page](https://cloud.elastic.co/cloud-pricing-table?productType=serverless).
 
 This pricing model differs from the existing [Machine Learning Nodes](https://www.elastic.co/docs/explore-analyze/machine-learning/data-frame-analytics/ml-trained-models), which is billed through VCUs consumed.