fix: Make returned collections respect explicit transactions (#2385)

## Relevant issue(s)

Resolves #2384

## Description

Makes returned collections respect explicit transactions.

client/db.go

@@ -187,13 +187,19 @@ type Store interface {
 	// GetCollectionByName attempts to retrieve a collection matching the given name.
 	//
 	// If no matching collection is found an error will be returned.
+	//
+	// If a transaction was explicitly provided to this [Store] via [DB].[WithTxn], any function calls
+	// made via the returned [Collection] will respect that transaction.
 	GetCollectionByName(context.Context, CollectionName) (Collection, error)
 
 	// GetCollections returns all collections and their descriptions matching the given options
 	// that currently exist within this [Store].
 	//
 	// Inactive collections are not returned by default unless a specific schema version ID
 	// is provided.
+	//
+	// If a transaction was explicitly provided to this [Store] via [DB].[WithTxn], any function calls
+	// made via the returned [Collection]s will respect that transaction.
 	GetCollections(context.Context, CollectionFetchOptions) ([]Collection, error)
 
 	// GetSchemaByVersionID returns the schema description for the schema version of the

db/txn_db.go

@@ -79,7 +79,12 @@ func (db *implicitTxnDB) GetCollectionByName(ctx context.Context, name string) (
 
 // GetCollectionByName returns an existing collection within the database.
 func (db *explicitTxnDB) GetCollectionByName(ctx context.Context, name string) (client.Collection, error) {
-	return db.getCollectionByName(ctx, db.txn, name)
+	col, err := db.getCollectionByName(ctx, db.txn, name)
+	if err != nil {
+		return nil, err
+	}
+
+	return col.WithTxn(db.txn), nil
 }
 
 // GetCollections gets all the currently defined collections.
@@ -101,7 +106,16 @@ func (db *explicitTxnDB) GetCollections(
 	ctx context.Context,
 	options client.CollectionFetchOptions,
 ) ([]client.Collection, error) {
-	return db.getCollections(ctx, db.txn, options)
+	cols, err := db.getCollections(ctx, db.txn, options)
+	if err != nil {
+		return nil, err
+	}
+
+	for i := range cols {
+		cols[i] = cols[i].WithTxn(db.txn)
+	}
+
+	return cols, nil
 }
 
 // GetSchemaByVersionID returns the schema description for the schema version of the