Revisit Plotly.js compatibility with strict CSP

https://github.com/plotly/plotly.js/pull/7109 was added in to make Plotly.js work better in strict CSP environments (specifically, ones which disallow inline CSS); however, it seems some of that work was broken by the migration to ESBuild.

For example, we no longer produce a separate plotly.css file (see recent comments on that PR).

@camdecoster recently added #7527 which makes it easier to test different CSPs in the devtools.

There's at least one obvious issue when inline styles are disallowed, which is that the modebar button styling is completely broken:

首先审查 PR #7109 及其最近的评论，然后检查 ESBuild 迁移和 issue #7527 的 CSP 测试设置。在不允许使用 inline CSS 时复现 modebar 按钮样式失效的问题，并检查是否会生成单独的 plotly.css 文件。当严格 CSP 环境仍能保留正常工作的 modebar 样式，并且相关 build 输出得到验证时，即视为完成。