Dialog: Fix dialog body correctly break long words

[iamkun]

fix #14855

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[d--j]

This is too aggressive. word-break: break-all; breaks apart words even when it is not necessary.
It is common to nest e.g. an <el-table> inside an <el-dialog>. Then all columns of that table inherit the word-break: break-all; and you explicitly need to overwrite that so that the layout does not gets broken.

See https://jsfiddle.net/5c9x3p6e/

Maybe overflow-wrap: break-word; is better – or leave #14855 to be fixed on a case by case basis (when you have long lines in a tiny <el-dialog>, add your own CSS like in https://jsfiddle.net/dLsnc8v4/ )