[Bug]: Engineers ringing a mex that already has one or more mass storages will queue a T3 upgrade before building the other mass storages.

### Describe the Bug

Using the relevant game setting, it is possible to take a group of engineers and by assisting a mex, queue up the upgrade to T2. When that mex is assisted again, the engineers will queue 4 mass storages around around the mex. Once those mass storages are built, another assist will queue the T3 upgrade for that mex.

However, if a mex already has a mass storage, which may happen because the building of queued storages was aborted, the engineers will queue and start a T3 upgrade before they've finished ringing the storages.

This causes T3 mexes to be inadvertendly started way before they should. It is not uncommon to see a group of engineers going around trying to ring all mexes, but then accidentally upgrading one mex to T3 while several mexes still awaiting mass storage rings.

The logic should check if the mex is fully ringed before being allowed to queue a T3 upgrade.

### Reproduce the bug

Build one mass extractor to T2 and add one mass storage. Assist the mex with engineers, and observe that they'll start the T3 upgrade rather than build the rings.

### Screenshots

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### Additional context

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