fix: Removed unnecessary check in useTheme()

[0xsimka]

What changed? Why?
The if (context === undefined) check in useTheme() was removed. This check was unnecessary because useContext(ThemeContext) never returns undefined—it always provides a value from createContext(). If no provider is found, the default value is used. This change makes the code cleaner and more logical.

Notes to reviewers
This is a minor cleanup to remove redundant logic. No functional changes expected.

How has it been tested?
Checked that the theme logic still works as expected without the unnecessary check.

Have you tested the following pages?

BaseWeb

• base.org
• base.org/names
• base.org/builders
• base.org/ecosystem
• base.org/name/jesse
• base.org/manage-names
• base.org/resources

BaseDocs

• docs.base.org
• docs sub-pages

[vercel]

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[cb-heimdall]

🟡 Heimdall Review Status

Requirement	Status	More Info
Reviews	🟡 0/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 0 Sum 1