Rating: Webchat dies when variant=emoji and precision=0.5

[antonxt]

When the aforementioned combo is selected in the message payload, then the browser console shows this error and the whole webchat breaks (empty page).

Possible solution: in case of out-of-range values for the given variant, fall back to the nearest value that makes sense. E.g. consider precision=1 even when the message has precision=0.5

webchat.legacy.js:279 TypeError: Cannot read property 'label' of undefined
    at getLabelText (rating.webchat-plugin.js:966)
    at he (rating.webchat-plugin.js:379)
    at rating.webchat-plugin.js:379
    at Array.map (<anonymous>)
    at rating.webchat-plugin.js:379
    at Array.map (<anonymous>)
    at rating.webchat-plugin.js:379
    at da (webchat.legacy.js:279)
    at Ua (webchat.legacy.js:279)
    at Ts (webchat.legacy.js:279)
ps @ webchat.legacy.js:279
Ls.n.callback @ webchat.legacy.js:279
ki @ webchat.legacy.js:279
wi @ webchat.legacy.js:279
wu @ webchat.legacy.js:279
t.unstable_runWithPriority @ webchat.legacy.js:287
Jo @ webchat.legacy.js:279
vu @ webchat.legacy.js:279
su @ webchat.legacy.js:279
(anonymous) @ webchat.legacy.js:279
t.unstable_runWithPriority @ webchat.legacy.js:287
Jo @ webchat.legacy.js:279
Xo @ webchat.legacy.js:279
$o @ webchat.legacy.js:279
nu @ webchat.legacy.js:279
enqueueSetState @ webchat.legacy.js:279
w.setState @ webchat.legacy.js:271
(anonymous) @ webchat.legacy.js:322
b @ webchat.legacy.js:6
(anonymous) @ webchat.legacy.js:322
(anonymous) @ webchat.legacy.js:322
(anonymous) @ webchat.legacy.js:322
(anonymous) @ webchat.legacy.js:322
(anonymous) @ webchat.legacy.js:322
(anonymous) @ webchat.legacy.js:322
(anonymous) @ webchat.legacy.js:322
u.emit @ webchat.legacy.js:6
(anonymous) @ webchat.legacy.js:263
r.emit @ webchat.legacy.js:263
m.onevent @ webchat.legacy.js:263
m.onpacket @ webchat.legacy.js:263
(anonymous) @ webchat.legacy.js:263
r.emit @ webchat.legacy.js:263
m.ondecoded @ webchat.legacy.js:263
(anonymous) @ webchat.legacy.js:263
r.emit @ webchat.legacy.js:320
f.add @ webchat.legacy.js:6
m.ondata @ webchat.legacy.js:263
(anonymous) @ webchat.legacy.js:263
r.emit @ webchat.legacy.js:6
f.onPacket @ webchat.legacy.js:320
(anonymous) @ webchat.legacy.js:320
r.emit @ webchat.legacy.js:6
i.onPacket @ webchat.legacy.js:6
i.onData @ webchat.legacy.js:6
ws.onmessage @ webchat.legacy.js:322
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webchat.legacy.js:279 Uncaught TypeError: Cannot read property 'label' of undefined
    at getLabelText (rating.webchat-plugin.js:966)
    at he (rating.webchat-plugin.js:379)
    at rating.webchat-plugin.js:379
    at Array.map (<anonymous>)
    at rating.webchat-plugin.js:379
    at Array.map (<anonymous>)
    at rating.webchat-plugin.js:379
    at da (webchat.legacy.js:279)
    at Ua (webchat.legacy.js:279)
    at Ts (webchat.legacy.js:279)