Fix freezing and crashing

[josh-flyclops]

There were 2 situations where an endless loop would occur. This happens when the bottom of scrolling is reached and we want to load more:

• When the selected tab gets changed while we try to load more gifs.
• When there are no more results to load and the end has been reached.

[coveralls-official]

Pull Request Test Coverage Report for Build 19746574386

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 1 (0.0%) changed or added relevant line in 1 file are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.1%) to 57.547%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
lib/src/components/tab_view.dart	0	1	0.0%

Files with Coverage Reduction	New Missed Lines	%
lib/src/components/tab_view.dart	1	24.83%

Totals
Change from base Build 19153161071:	-0.1%
Covered Lines:	305
Relevant Lines:	530

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💛 - Coveralls

[LegendAF]

Nice catch