Auto merge of #14567 - szeged:represented-attributes, r=jdm

Check if represented attributes are cached

<!-- Please describe your changes on the following line: -->
Improve existing cache checks in `/bluetooth/lib.rs`, and update Step comments in `script/dom` corresponding to this.

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] There are tests for these changes OR

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tests/wpt/mozilla/meta/mozilla/bluetooth/connect/device-goes-out-of-range.html.ini

@@ -1,5 +0,0 @@
-[device-goes-out-of-range.html]
-  type: testharness
-  [Device goes out of range. Reject with NetworkError.]
-    expected: FAIL
-