* fix(components): [watermark] Support for lower versions of Firefox
fontBoundingBoxAscent属性在firefox V116版本才支持,在低版本firefox中,采用 actualBoundingBoxAscent 进行向下兼容,可以支持到
firefox V74
* chore(components): [watermark] add a line of comments for the processing
* perf(components): [watermark] change "!=" to "!=="
* feat(components): watermark component
be able to set text,multi-text,image as watermark
* docs(components): update image watermark example
update the image for dark mode