fix(disqusclick): let disqus_click_to_load button automatically hide

[neoFelhz]

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What kind of change does this PR introduce? (check one with "x")

• Bug fix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
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Does this PR introduce a breaking change? (check one with "x")

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• No

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Description
fix a bug about disqus_click_to_load button can't automatically hide after the disqus comments has already loaded

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Verification steps

• Check the changed files
• Configure _config.yml in Material on line 179 as "disqus_click", then run a hexo clean hexo g & hexo s to find out whether it is working.