make sure embedding fits (#240)

* make sure embedding fits

* fix test fail

Author: vswamidass-sfdc

app/controllers/concerns/gpt_concern.rb

@@ -83,9 +83,12 @@ def call_salesforce_connect_gpt_embedding(input)
     access_token = oauth_token['access_token']
     instance_url = oauth_token['instance_url']
 
+    # 15000 characters is about equivalent to 8192 tokens for the text-embedding-ada-002 model.
+    truncated_input = input.truncate(15000.to_i)
+
     new_endpoint_url = "#{instance_url}/services/data/v58.0/einstein/llm/embeddings"
     request_body = {
-      prompts: { wrappedListString: [input] },
+      prompts: { wrappedListString: [truncated_input] },
       additionalConfig: {
         applicationName: 'fack',
         model: ENV.fetch('EMBEDDING_MODEL','llmgateway__AzureOpenAITextEmbeddingAda_002')