[8.x] Make assertSee, assertSeeText, assertDontSee and assertDontSeeText accept an array

[johnRivs]

This PR allows assertSee, assertSeeText, assertDontSee and assertDontSeeText to work with arrays. Unlike the -InOrder methods, these won't check the order.

Before:

$this->get('/')
    ->assertSee('some')
    ->assertSee('piece')
    ->assertSee('of')
    ->assertSee('text');

After:

$this->get('/')
    ->assertSee(['some', $foo, 'text', 'piece', 'of']);

Benefits

It's mostly a code style change. In projects where the frontend can change unexpectedly, this will avoid errors because of the order while keeping things compact

Notes

• I considered doing more type checking and throw a TypeError. The idea was to provide a bit more feedback than htmlspecialchars() expects parameter 1 to be string, _______ given but I'm not too sure about it.
• I'm running assertStringContainsString inside a foreach because I don't know if there's a better PHPUnit assertion for this case. This makes it so OK (1 test, 3 assertions) shows several assertions (one for each item in the array) which never bothered me. I'm guessing copying the strategy used in Illuminate\Testing\Constraints\SeeInOrder could deal with this?
• First PR here. Open to any correction or suggestion.

[taylorotwell]

You can make your code simpler by just always using Arr::wrap($value) on the passed argument so that you can always loop over it and not have to check is_array.

[johnRivs]

Ahh, I thought about that but didn't know about Arr::wrap so I discarded the idea thinking I had to do the check anyway.

[johnRivs]

Earlier I saw I was able to add commits to the PR. I'm guessing now that it's merged I'd have to open a new one, right? (It's for the Arr::wrap cleanup)

[driesvints]

@johnRivs yeah a new PR will be needed if this one is already merged.

[johnRivs]

Turns out Taylor already cleaned it up haha Thanks, both of ya!