Number tag does not work and causes ui to break

The `Number` tag seems to be broken and causes issues even when rendering a self hosted lb.

Tried it on the playground and here is the console error:
```
Uncaught Error: No model registered for tag: number
Available models:
audio
audioplus
hypertext
polygonregion
brushregion
keypointregion
rectangleregion
ellipseregion
image
text
channel
timeseries
label
labels
paragraphlabels
textarearegion
textarea
choice
choices
rating
paragraphs
video
brush
brushlabels
hypertextlabels
keypoint
keypointlabels
list
pairwise
polygon
polygonlabels
ranker
rectangle
rectanglelabels
shortcut
taxonomy
timeserieslabels
ellipse
ellipselabels
relations
relation
dialog
header
table
view
style
filter
panel
collapse
timeseriesregion
at e.value (Registry.js:99:13)
at e.value (ConfigValidator.js:234:30)
at e.value (index.js:67:27)
at Object.validate (CompletionStore.js:947:23)
at be (mobx.module.js:928:19)
at r (mobx.module.js:915:16)
at mobx-state-tree.module.js:2593:35
at ke (mobx-state-tree.module.js:2456:16)
at Object.r (mobx-state-tree.module.js:2483:16)
at Object.o (CompletionStore.js:791:12)
```