Remove default sendToken value in send.component.js

[tmashuang]

Fixes #8763

[metamaskbot]

Builds ready [ee0acd4]

• builds: chrome, firefox, opera
• bundle viz: background, ui, inpage, contentscript, ui-libs, bg-libs, phishing-detect
• dep viz: background
• all artifacts

Page Load Metrics (585 ± 60 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	30	49	36	5	3
		domContentLoaded	353	787	583	126	60
		load	355	788	585	126	60
		domInteractive	353	787	583	126	60

[whymarrh]

Though if sendToken is undefined or null this will throw now 🤔

[Gudahtt]

I suspect that this PR would fix the bug, but only because estimateGas is never called with sendToken set to null or undefined.

It's only called by updateGasData in actions.js, which itself is only called by updateAndSetGasLimit in send.container.js, which is only called in one spot in send.component.js, where sendToken is given a default value of {}:

metamask-extension/ui/app/pages/send/send.component.js

Line 263 in 2873053

sendToken = {},

state.metamask.send.token is always set to undefined when there is no sendToken, so that default should always be set. But only for a very tenuous reason.

It would seem better to remove the = {} instead.

[metamaskbot]

Builds ready [fc6bc43]

• builds: chrome, firefox, opera
• bundle viz: background, ui, inpage, contentscript, ui-libs, bg-libs, phishing-detect
• dep viz: background
• all artifacts

Page Load Metrics (695 ± 28 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	33	103	47	20	10
		domContentLoaded	497	809	693	59	28
		load	499	810	695	59	28
		domInteractive	496	808	693	59	28

[Gudahtt]

LGTM!