[lexical][lexical-table] Bug Fix: Allow TableSelection to be preserved during contextmenu events

[etrepum]

Description

LexicalEvents traps all pointerdown events to update the selection later on pointerup, but it doesn't check for the button so this also updates selection on contextmenu events.

Also refactors a lot of our DOM guards to consistently use functions like isHTMLElement or the new isDOMNode rather than using instanceof (not compatible with frames) or casts (unsafe). These functions now accept unknown rather than a specific type such as EventType or Node for ease of use without any real loss of safety.

Closes #6941

Test plan

Before

playground url

lexical-table-selection-contextmenu-before.mov

After

PR playground url

lexical-table-selection-contextmenu-after.mov

[vercel]

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Name	Status	Preview	Comments	Updated (UTC)
lexical	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Dec 14, 2024 6:07pm
lexical-playground	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Dec 14, 2024 6:07pm

[github-actions]

size-limit report 📦

Path	Size
lexical - cjs	31.2 KB (0%)
lexical - esm	31.04 KB (0%)
@lexical/rich-text - cjs	40.16 KB (0%)
@lexical/rich-text - esm	32.95 KB (0%)
@lexical/plain-text - cjs	38.77 KB (0%)
@lexical/plain-text - esm	30.16 KB (0%)
@lexical/react - cjs	42.05 KB (0%)
@lexical/react - esm	34.24 KB (0%)