chore: add toggle content prop on Dropdown

[goga-m]

Summary

Adds the feature to accept toggleContent to render custom elements.
Accepts function as a prop and provides isOpen state to render dynamically.

Example:

As element:

<Dropdown
	options={options}
	toggleContent={<div>sample toggle content</div>}>
</Dropdown>

As a function:

<Dropdown
	options={options}
	toggleContent={(isOpen) => (<div>sample toggle content</div>)}>
</Dropdown>

Checklist

• Documentation (if necessary)
• Tests (if necessary)
• Ready to be merged

[codecov]

Codecov Report

Merging #2142 into 3.0-react will not change coverage.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##           3.0-react     #2142    +/-   ##
============================================
  Coverage     100.00%   100.00%            
============================================
  Files             45        96    +51     
  Lines            298       734   +436     
  Branches          49       112    +63     
============================================
+ Hits             298       734   +436     

Flag	Coverage Δ
#unit	100.00% <100.00%> (?)

Impacted Files	Coverage Δ
src/app/components/Button/Button.tsx	100.00% <ø> (ø)
src/app/components/Card/Card.tsx	100.00% <ø> (ø)
src/app/components/Card/CardControl.tsx	100.00% <ø> (ø)
src/app/components/Circle/Circle.tsx	100.00% <ø> (ø)
src/app/components/Divider/Divider.styles.ts	100.00% <ø> (ø)
src/app/components/Divider/Divider.tsx	100.00% <ø> (ø)
src/app/components/Form/FormLabel.tsx	100.00% <ø> (ø)
src/app/components/Select/Select.tsx	100.00% <ø> (ø)
...app/components/SideBar/SideBarItem/SideBarItem.tsx	100.00% <ø> (ø)
src/app/components/StepIndicator/StepIndicator.tsx	100.00% <ø> (ø)
... and 101 more

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