Fix IPv6 parsing in API access methods and custom DNS

[rablador]

Acceptance criteria:

• Adding IPv6 addresses should work, whilst the app should still reject any arbitrary unsigned 32 bit integer instead of interpreting that as an IPv4 address.
• Custom DNS and API access method code should use the same validation for IP addresses.
• Using IPv6 addresses in custom API methods and custom DNS works.
• The validation code must be unit tested.
• When this is fixed, it should be mentioned in the changelog.

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This change is 

[linear]

IOS-696 IPv6 parsing fails in API connection methods and custom DNS too.

[mojganii]

Reviewable status: 0 of 5 files reviewed, 1 unresolved discussion (waiting on @rablador)

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ios/MullvadVPNTests/MullvadTypes/AnyIPAddressTests.swift line 25 at r1 (raw file):

        XCTAssertNotNil(AnyIPAddress("2a03:1b20:1:f011::bb09"))
        XCTAssertNotNil(AnyIPAddress("FE80:0000:0000:0000:0202:B3FF:FE1E:8329"))
    }

I suggest to add more IPs to be tested out:

Code snippet:

        XCTAssertNotNil(AnyIPAddress("2001:0db8:0000:0042:0000:8a2e:0370:7334"))
        XCTAssertNotNil(AnyIPAddress("2001:db8::42:0:8a2e:370:7334"))
        XCTAssertNotNil(AnyIPAddress("::1"))
        XCTAssertNotNil(AnyIPAddress("::"))
        XCTAssertNotNil(AnyIPAddress("::ffff:192.168.1.1"))
        XCTAssertNotNil(AnyIPAddress("fe80::1ff:fe23:4567:890a"))
        XCTAssertNotNil(AnyIPAddress("ff02::1"))
        XCTAssertNotNil(AnyIPAddress("2001:0db8:85a3::8a2e:0370:7334"))
        XCTAssertNotNil(AnyIPAddress("fc00::1234:5678:abcd"))

[mojganii]

Reviewable status: 0 of 5 files reviewed, 1 unresolved discussion (waiting on @rablador)

[rablador]

Reviewable status: 0 of 5 files reviewed, 1 unresolved discussion (waiting on @mojganii)

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ios/MullvadVPNTests/MullvadTypes/AnyIPAddressTests.swift line 25 at r1 (raw file):

Previously, mojganii wrote…

I suggest to add more IPs to be tested out:

Done.

[buggmagnet]

Reviewed 2 of 5 files at r1, 2 of 2 files at r2, all commit messages.
Reviewable status: 4 of 5 files reviewed, 1 unresolved discussion (waiting on @mojganii)

[mojganii]

Reviewable status: 2 of 5 files reviewed, 1 unresolved discussion (waiting on @buggmagnet)

[github-actions]

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