fix(backend): add back perplexity_llama (#10327)

<!-- Clearly explain the need for these changes: -->

We flew too close to the sun

### Changes 🏗️
adds back perplexity due to the need to remove it after it has already
been migrated not before or the system will automatically migrate it to
a different model so that it is one that exists

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-->

### Checklist 📋

#### For code changes:
- [x] I have clearly listed my changes in the PR description
- [x] I have made a test plan
- [x] I have tested my changes according to the test plan:
  <!-- Put your test plan here: -->
  - [x] tested locally; no impact since we are simply re-enabling it

autogpt_platform/backend/backend/blocks/llm.py

@@ -124,6 +124,9 @@ class LlmModel(str, Enum, metaclass=LlmModelMeta):
     COHERE_COMMAND_R_PLUS_08_2024 = "cohere/command-r-plus-08-2024"
     EVA_QWEN_2_5_32B = "eva-unit-01/eva-qwen-2.5-32b"
     DEEPSEEK_CHAT = "deepseek/deepseek-chat"  # Actually: DeepSeek V3
+    PERPLEXITY_LLAMA_3_1_SONAR_LARGE_128K_ONLINE = (
+        "perplexity/llama-3.1-sonar-large-128k-online"
+    )
     PERPLEXITY_SONAR = "perplexity/sonar"
     PERPLEXITY_SONAR_PRO = "perplexity/sonar-pro"
     PERPLEXITY_SONAR_DEEP_RESEARCH = "perplexity/sonar-deep-research"
@@ -226,6 +229,9 @@ MODEL_METADATA = {
     LlmModel.COHERE_COMMAND_R_PLUS_08_2024: ModelMetadata("open_router", 128000, 4096),
     LlmModel.EVA_QWEN_2_5_32B: ModelMetadata("open_router", 16384, 4096),
     LlmModel.DEEPSEEK_CHAT: ModelMetadata("open_router", 64000, 2048),
+    LlmModel.PERPLEXITY_LLAMA_3_1_SONAR_LARGE_128K_ONLINE: ModelMetadata(
+        "open_router", 127072, 127072
+    ),
     LlmModel.PERPLEXITY_SONAR: ModelMetadata("open_router", 127000, 127000),
     LlmModel.PERPLEXITY_SONAR_PRO: ModelMetadata("open_router", 200000, 8000),
     LlmModel.PERPLEXITY_SONAR_DEEP_RESEARCH: ModelMetadata(

autogpt_platform/backend/backend/data/block_cost_config.py

@@ -84,6 +84,7 @@ MODEL_COST: dict[LlmModel, int] = {
     LlmModel.COHERE_COMMAND_R_PLUS_08_2024: 3,
     LlmModel.EVA_QWEN_2_5_32B: 1,
     LlmModel.DEEPSEEK_CHAT: 2,
+    LlmModel.PERPLEXITY_LLAMA_3_1_SONAR_LARGE_128K_ONLINE: 1,
     LlmModel.PERPLEXITY_SONAR: 1,
     LlmModel.PERPLEXITY_SONAR_PRO: 5,
     LlmModel.PERPLEXITY_SONAR_DEEP_RESEARCH: 10,