Fixed deferred SVGs that use mask, defs or use tags

[AEM5299]

Hi,

SVGs that has mask, defs or use tags don't get deferred correctly, since the strip_tags function call removes them from the sag content (an example svg is attached at the end).

This PR adds these tags to the allowed list for strip_tags.

Example SVG that use the 3 tags 👇

<svg width="60" height="60" viewBox="0 0 60 60" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
  <defs>
    <path d="M0 29.997495C0 46.567015 13.427975 60 30.002505 60 46.567015 60 60 46.567015 60 29.997495 60 13.432985 46.567015 0 30.002505 0 13.427975 0 0 13.432985 0 29.997495Z" id="fodmap-a"/>
    <path d="M15.685498 3.670797C2.64507 10.886334-3.260408 26.270404 1.80359 40.303137c3.280262 9.091274 9.639234 15.2328 18.784665 18.459875.408143.141184.745743.226903 1.022877.236988h.100776c.665122-.025211.92714-.529442.891869-1.699256-.105815-3.101018.146125-6.222204-.095738-9.303052-.403104-5.0776 3.824453-8.718143 8.591162-8.460986 3.900035.206735 7.825264.095804 11.730338.005043 2.7008-.060508 4.252751-1.724468 4.167092-4.175028-.08566-2.279122-1.72831-3.711136-4.378722-3.731305-4.04616-.02017-8.09232 0-12.13848 0-1.360478 0-2.715916.010084-4.076394.025211-2.957778.030254-5.920595.060508-8.868296-.070592-5.376405-.226904-8.581085-5.985215-6.177575-10.760277 1.451176-2.899325 3.814376-4.255705 6.978745-4.301085 4.111665-.060508 8.228368-.050423 12.334994-.141185 3.174447-.070592 4.51477-1.482437 4.539963-4.659089.020155-3.232117-.04031-6.474318.025194-9.711477.025194-1.321084-.569385-1.81523-1.76862-1.905991C32.479834.040338 31.492228 0 30.5147 0c-5.189969 0-10.168308 1.09418-14.829202 3.670797Z" id="fodmap-c"/>
    <path d="M24.539044 1.93889c-.005033 2.724387.005033 5.453746.0151 8.178134.0151 5.210143-3.110582 8.25768-8.44085 8.247736-3.840411-.009943-7.680822-.019886-11.5162.009943-2.81865.019886-4.660839 1.635627-4.595406 3.942408.0604 2.306781 1.726423 3.738576 4.535007 3.763434 4.107176.044743 8.214352.009943 12.321528.009943v-.034801h5.657433c1.952922.004971 3.905844.014915 5.863799.019886 4.721239.004972 8.179119 3.19171 8.158985 7.521896-.025166 4.330185-3.462913 7.482123-8.199252 7.511952-3.905843.019886-7.811687.014915-11.71753.059658-3.437747.039772-4.711173 1.332365-4.731306 4.757736-.020134 3.19171.130866 6.388391-.0604 9.57513-.115766 1.90906.649296 2.366438 2.370686 2.455925 14.13855.750699 27.230174-8.605684 30.80382-22.093393C48.905267 21.163721 41.03318 5.861411 26.809063.477265 26.02387.178975 25.510472 0 25.178274 0c-.583864 0-.634197.541895-.63923 1.93889Z" id="fodmap-e"/>
  </defs>
  <g fill="none" fill-rule="evenodd">
    <g>
      <mask id="fodmap-b" fill="#fff">
        <use xlink:href="#fodmap-a"/>
      </mask>
      <path fill="#008C47" mask="url(#fodmap-b)" d="M-5.010438 65.010438h70.020876V-5.010438H-5.010438z"/>
    </g>
    <g>
      <mask id="fodmap-d" fill="#fff">
        <use xlink:href="#fodmap-c"/>
      </mask>
      <path fill="#78BE44" mask="url(#fodmap-d)" d="M-5.039107 64.042304h57.074543V-5.042304H-5.039107z"/>
    </g>
    <g transform="translate(14 2)">
      <mask id="fodmap-f" fill="#fff">
        <use xlink:href="#fodmap-e"/>
      </mask>
      <path fill="#008C47" mask="url(#fodmap-f)" d="M-5.036649 62.974125h56.071004V-4.971511H-5.036649z"/>
    </g>
    <path fill="#FAFCFA" d="M28.4975 39.5h-.715 1.435z"/>
  </g>
</svg>

[driesvints]

Thanks. Released that.