refactor: Remove LanceDB fallback (#1683)

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## Description
Remove fallback when provided vector adapter is not reckognized to use
LanceDB. When no adapter provider info is provided LanceDB will still be
used.

## Type of Change
<!-- Please check the relevant option -->
- [ ] Bug fix (non-breaking change that fixes an issue)
- [ ] New feature (non-breaking change that adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update
- [x] Code refactoring
- [ ] Performance improvement
- [ ] Other (please specify):

## Screenshots/Videos (if applicable)
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## Pre-submission Checklist
<!-- Please check all boxes that apply before submitting your PR -->
- [ ] **I have tested my changes thoroughly before submitting this PR**
- [ ] **This PR contains minimal changes necessary to address the
issue/feature**
- [ ] My code follows the project's coding standards and style
guidelines
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] I have added necessary documentation (if applicable)
- [ ] All new and existing tests pass
- [ ] I have searched existing PRs to ensure this change hasn't been
submitted already
- [ ] I have linked any relevant issues in the description
- [ ] My commits have clear and descriptive messages

## DCO Affirmation
I affirm that all code in every commit of this pull request conforms to
the terms of the Topoteretes Developer Certificate of Origin.

cognee/infrastructure/databases/vector/create_vector_engine.py

@@ -47,7 +47,7 @@ def create_vector_engine(
             embedding_engine=embedding_engine,
         )
 
-    if vector_db_provider == "pgvector":
+    if vector_db_provider.lower() == "pgvector":
         from cognee.infrastructure.databases.relational import get_relational_config
 
         # Get configuration for postgres database
@@ -78,7 +78,7 @@ def create_vector_engine(
             embedding_engine,
         )
 
-    elif vector_db_provider == "chromadb":
+    elif vector_db_provider.lower() == "chromadb":
         try:
             import chromadb
         except ImportError:
@@ -94,7 +94,7 @@ def create_vector_engine(
             embedding_engine=embedding_engine,
         )
 
-    elif vector_db_provider == "neptune_analytics":
+    elif vector_db_provider.lower() == "neptune_analytics":
         try:
             from langchain_aws import NeptuneAnalyticsGraph
         except ImportError:
@@ -122,7 +122,7 @@ def create_vector_engine(
             embedding_engine=embedding_engine,
         )
 
-    else:
+    elif vector_db_provider.lower() == "lancedb":
         from .lancedb.LanceDBAdapter import LanceDBAdapter
 
         return LanceDBAdapter(
@@ -130,3 +130,9 @@ def create_vector_engine(
             api_key=vector_db_key,
             embedding_engine=embedding_engine,
         )
+
+    else:
+        raise EnvironmentError(
+            f"Unsupported graph database provider: {vector_db_provider}. "
+            f"Supported providers are: {', '.join(list(supported_databases.keys()) + ['LanceDB', 'PGVector', 'neptune_analytics', 'ChromaDB'])}"
+        )