Handle `getTokenData` command missing

[puddly]

Some versions of EmberZNet do not include the command at all, even if it is defined in the EZSP version.

https://github.com/home-assistant/core/issues/95632

[codecov[bot]]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (cb3d4f8) 99.77% compared to head (052ddf9) 99.77%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## dev #571 +/- ## ======================================= Coverage 99.77% 99.77% ======================================= Files 67 67 Lines 4836 4837 +1 ======================================= + Hits 4825 4826 +1 Misses 11 11 ``` | [Impacted Files](https://app.codecov.io/gh/zigpy/bellows/pull/571?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=zigpy) | Coverage Δ | | |---|---|---| | [bellows/exception.py](https://app.codecov.io/gh/zigpy/bellows/pull/571?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=zigpy#diff-YmVsbG93cy9leGNlcHRpb24ucHk=) | `100.00% <100.00%> (ø)` | | | [bellows/ezsp/\_\_init\_\_.py](https://app.codecov.io/gh/zigpy/bellows/pull/571?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=zigpy#diff-YmVsbG93cy9lenNwL19faW5pdF9fLnB5) | `99.30% <100.00%> (-0.01%)` | :arrow_down: | | [bellows/ezsp/protocol.py](https://app.codecov.io/gh/zigpy/bellows/pull/571?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=zigpy#diff-YmVsbG93cy9lenNwL3Byb3RvY29sLnB5) | `97.29% <100.00%> (ø)` | |

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[puddly]

Tested with HUSBZB-1, SkyConnect running EZSP v7.1.3.0 and v7.3.3.0, and RCP v7.3.3.0.