chore: update mlx to 0.26.2

[xlab]

• Disable CUDA explicitly in build config
• Config fix for backend/no_metal move to backend/metal/no_metal.cpp

[davidkoski]

One of the export tests is failing -- I looked into it and it is a bug in the test:

--- a/Tests/MLXTests/ExportTests.swift
+++ b/Tests/MLXTests/ExportTests.swift
@@ -52,7 +52,7 @@ class ExportTests: XCTestCase {
             [arrays.dropFirst().reduce(arrays[0], +)]
         }
 
-        let x = MLXArray(1)
+        let x = MLXArray([1, 2, 3])
 
         try exportFunctions(to: url, shapeless: true, f) { export in
             try export(x)

dimensions of input did not match between save (0) and call (1)