acc: do not fail the test if testserver failed to read the body (#3589)

This happens sometimes

```
=== FAIL: acceptance TestAccept/bundle/upload/internal_server_error/DATABRICKS_CLI_DEPLOYMENT=direct-exp (0.05s)
    acceptance_test.go:1328: No effective updates from BundleConfig.default_name
    server.go:59: Failed to read request body: unexpected EOF
```

Reproducible with:
`go test ./acceptance -run
^TestAccept$/^bundle$/^upload$/^internal_server_error$ -v -count=100
-failfast`

The issue started after disabling rate limit in acc tests
#3581
if I restore the rate limit, it does not fail even without this patch:

`DATABRICKS_RATE_LIMIT=15 go test ./acceptance -run
^TestAccept$/^bundle$/^upload$/^internal_server_error$/direct -v
-count=100 -failfast` succeeds.

Author: denik

libs/testserver/server.go

@@ -56,7 +56,7 @@ type EncodedResponse struct {
 func NewRequest(t testutil.TestingT, r *http.Request, fakeWorkspace *FakeWorkspace) Request {
 	body, err := io.ReadAll(r.Body)
 	if err != nil {
-		t.Fatalf("Failed to read request body: %s", err)
+		t.Logf("Error while reading request body: %s", err)
 	}
 
 	return Request{