[FIX] mail: outlook 365 warning not hiding mail

It seems that there is a rather frequent warning that can be added to
mail received by outlook 365 and that has the form:

```
<table border="0" cellspacing="0" cellpadding="0" align="left" width="100%" style="width:100.0%">
...Caution: This is an external email and has a suspicious subject or content...
</table>
```

The combination of `align="left" width="100%"` means that a div after
this alert will probably have a width of 0 (because the previous content
is floating to the left, and taking 100% of width so there is 0 pixel of
width remaining).

This is not an issue in general, but in Odoo this conflicts with a code
that adds scrollbar if a message content overflows (but here since width
is 0 pixel the content is just hidden).

With this commit, if we detect the code that is used in all our received
report (width=100% and float=left), we ignore the float to prevent this
issue from happening.

An alternative is to avoid Outlook 365 adding this structure in a
message (see [1]), but this is only possible if we can change the
configuration where this structure is added (eg. we can't if it is
a customer that is forwarding a mail already broken).

[1]: https://learn.microsoft.com/en-us/microsoft-365/security/office-365-security/set-up-anti-phishing-policies?view=o365-worldwide#first-contact-safety-tip



opw-2887342
opw-2925222
opw-2946587

closes odoo/odoo#102063

X-original-commit: ed7280ce
Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>
Signed-off-by: Nicolas Lempereur (nle) <nle@odoo.com>