fix(ui): tooltip background color override problem

[evenchange4]

Issue:

What I did

How to test

[michaelhsu-bot]

	Warnings
:warning:	:exclamation: Big PR

Generated by :no_entry_sign: dangerJS

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[evenchange4]

Deploy preview for mcslite ready!

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[evenchange4]

Deploy preview for mcs-lite-ui ready!

Built with commit 19277ab3bc723334a82a86df37443814838a9747

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[codecov[bot]]

Codecov Report

Merging #632 into master will not change coverage. The diff coverage is 100%.

@@           Coverage Diff           @@
##           master     #632   +/-   ##
=======================================
  Coverage   83.76%   83.76%           
=======================================
  Files         326      326           
  Lines        2691     2691           
  Branches      174      174           
=======================================
  Hits         2254     2254           
  Misses        372      372           
  Partials       65       65

Impacted Files	Coverage Δ
packages/mcs-lite-ui/src/Menu/Menu.js	100% <100%> (ø)	:arrow_up:
packages/mcs-lite-ui/src/Tooltip/Tooltip.js	66.66% <100%> (ø)	:arrow_up:
...s-lite-ui/src/DataPointAreaChart/RechartTooltip.js	100% <100%> (ø)	:arrow_up:
...s-lite-ui/src/MobileDeviceCard/MobileDeviceCard.js	100% <100%> (ø)	:arrow_up:
...mcs-lite-ui/src/DataChannelCard/DataChannelCard.js	100% <100%> (ø)	:arrow_up:
packages/mcs-lite-ui/src/Toast/Toast.js	100% <100%> (ø)	:arrow_up:
packages/mcs-lite-ui/src/Popover/Popover.js	60% <100%> (ø)	:arrow_up:

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