Fix di-web for theme pathMap configuration with multiple paths

[mariovials]

Allows you to use a directory array as the source of the view files, as described in the documentation of the Theme class

Q	A
Is bugfix?	✔️
New feature?	❌
Breaks BC?	❌

Without this, when configuring a theme with multiple paths, the following error occurs

'yiisoft/view' => [
    'theme' => [
        'pathMap' => [
            '/app/views' => [
                '/app/themes/christmas',
                '/app/themes/basic',
            ],
        ],
        ...
    ],
],

now you can set up a theme as described in the Theme documentation, for multiple cascading directories, as this is the main functionality of Theme

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.51%. Comparing base (071a326) to head (b8ab0ec).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##             master     #283   +/-   ##
=========================================
  Coverage     99.51%   99.51%           
  Complexity      305      305           
=========================================
  Files            19       19           
  Lines           827      827           
=========================================
  Hits            823      823           
  Misses            4        4           

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[vjik]

Looks good 👍

• add test
• add line to changelog