ServerFindMyTests: back to 0 dependencies alerts

Summary:
## What

Fix it so our builds no longer show a "dependencies" alert.

**Before**

```
[mheiber@devbig197]~/fbsource/fbcode/hphp/hack% dune clean && dune build single
Entering directory '/data/users/mheiber/fbsource/fbcode/hphp'
File "hack/src/server/serverFindMyTests.ml", line 42, characters 8-31:
42 |   match Decl_provider.get_class ctx (Utils.add_ns class_name) with
             ^^^^^^^^^^^^^^^^^^^^^^^
Alert dependencies: Decl_provider.get_class
```

**After**

```
[mheiber@devbig197]~/fbsource/fbcode/hphp/hack% dune clean && dune build single
```

This version of the diff has  TODO for explaining why we suppress the alert. Hoping reviewers (frankemrich) can help guide to what the TODO should say or suggest the best fix.

## Context

- decl_provider.mli and folded_class.mli have alerts that say not to use certain functions which are not fanout-aware and to use typing_env.mli functions instead
- serverFindMyTests.ml currently violates this

Differential Revision: D90113599

fbshipit-source-id: 802f9ce86c1e8dc9caaa296c6f078635b66b3792

Author: mheiber

hphp/hack/src/server/serverFindMyTests.ml

@@ -9,6 +9,11 @@
 open Hh_prelude
 open ServerEnv
 
+[@@@alert "-dependencies"]
+(* TODO: either use fanout-aware functions from typing env
+ * or update this comment to say why we don't need them
+ *)
+
 type member = Method of string
 
 let findrefs_member_of_member = function