Search percent sign bug

[ioancole]

This is another attempt at PR #4730

This includes the change suggested to fix the lingering bug from that commit.

PR Checklist

Please check all that apply to this PR using "x":

• I have checked that this PR is not a duplicate of an existing PR (open, closed or merged)
• I have checked that this PR does not introduce a breaking change
• This PR introduces breaking changes and I have provided a detailed explanation below

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting)
• Refactoring (no functional changes)
• Documentation changes
• Other - Please describe:

Fixes

Issue Number: 4516

What is the current behavior?

Search query containing '%' causes app crash

What is the new behavior?

Searches can now contain '%' character

Other information

Api request was breaking for main search and autocomplete when query string included symbols such as '%' and whitespace.
The ClaimPreview component was also throwing an exception when the claim URI was invalid, causing the app to crash.

This PR fixes all of the above, and includes a minor refactor of the wunderbar component view/index.
I have hidden the URI header in the search page (which contains the ClaimPreview component, and a couple of URI-related links) for inavlid URIs.

The search functionality still logs an error to the console when the search string contains whitespace - this comes from directly calling console.error(...) in the parseURI method (lbry-redux project). This should probably be improved at some point.

Thanks!